Detection light modulation device and illumination system

Abstract

The invention relates to the technical field of optical detection, in particular to a detection light modulation device and an illumination system.The detection light modulation device is used for being arranged between a light source and a diffractive optical element, and illumination light emitted by the light source is modulated through the detection light modulation device and the diffractive optical element in sequence and then forms a long-strip-shaped light spot on a sample to be detected; wherein illumination light emitted by the light source is modulated into a target light beam through the detection light modulation device, and the light intensity of the target light beam is in Gaussian distribution in the length direction of the long-strip-shaped light spot, so that the light intensity of the long-strip-shaped light spot is in flat-top distribution; the detection light modulation device at least comprises an image rotation assembly, the light intensity of the illumination light is in Gaussian distribution in the first preset direction, and the image rotation assembly is used for rotating the illumination light so that the first preset direction can coincide with the length direction of the long-strip-shaped light spot. The invention is at least beneficial to improving the stability of the detection light.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical detection, and in particular relates to a detection light modulation device and an illumination system. Background Art

[0002] The lighting system is one of the important components of wafer inspection equipment. In the lighting system, the illumination light emitted by the light source is generally modulated into detection light through a diffractive optical element. The diffractive optical element modulates the circular light spot emitted by the laser or other light source, which ideally conforms to the Gaussian distribution, into a linear illumination light spot (long strip light spot) at the illumination position. However, the flat-top light modulated and shaped by the diffractive optical element on the incident light cannot achieve a better beam shaping effect, has poor uniformity, and the light spot distribution deviates from the designed state, which seriously affects the detection accuracy.

[0003] Therefore, how to optimize the spot distribution of the linear illumination spot and thereby improve the wafer detection accuracy has become an urgent problem to be solved in the current lighting system. Summary of the invention

[0004] In view of this, the present invention aims to provide a detection light modulation device and an illumination system, which are at least beneficial to improving the stability of the detection light.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows: The invention provides a detection light modulation device, comprising: a detection light modulation device used to be arranged between a light source and a diffractive optical element, wherein the illumination light emitted by the light source is modulated by the detection light modulation device and the diffractive optical element in sequence to form a long strip light spot on a sample to be inspected; wherein the illumination light emitted by the light source is modulated into a target light beam by the detection light modulation device, and along the length direction of the long strip light spot, the light intensity of the target light beam is Gaussian distributed, so that the light intensity of the long strip light spot is flat-top distributed; the detection light modulation device at least comprises an image rotation component, and along a first preset direction, the light intensity of the illumination light is Gaussian distributed, and the image rotation component is used to rotate the illumination light, so that the first preset direction coincides with the length direction of the long strip light spot.

[0006] Furthermore, the detection light modulation device also includes a variable magnification lens assembly, the variable magnification lens assembly and the image rotation assembly are arranged along the light beam transmission direction, and the variable magnification lens assembly is used to adjust the size of the illumination light so that along the first preset direction, the size of the target light beam is a first target size.

[0007] Furthermore, the image rotation assembly and the zoom lens assembly are arranged in sequence along the light beam transmission direction.

[0008] Furthermore, the image rotation component is also used to adjust the light beam divergence angle to a target divergence angle so that the width of the long strip light spot is the target width.

[0009] Furthermore, the variable power lens group includes a plurality of concave-convex lenses, and the distance between any two adjacent concave-convex lenses is adjustable.

[0010] Furthermore, the zoom lens group includes three concave-convex lenses.

[0011] Furthermore, along the length direction of the long strip light spot, the uniformity parameter a of the light intensity of the long strip light spot is greater than 90%, a=1-(max-min) / (max+min), wherein max is the maximum value of the light intensity of the long strip light spot, and min is the minimum value of the light intensity within the distribution area of ​​the long strip light spot.

[0012] Furthermore, the detection light modulation device also includes a polarization adjustment component, which is located between the image rotation component and the light source, and is used to adjust the polarization direction of the illumination light so that the polarization direction of the target light beam is the target polarization direction.

[0013] Furthermore, the polarization adjustment component includes a plurality of rotatable wave plates arranged along the light path direction.

[0014] Furthermore, the polarization adjustment component includes: a 1 / 2 wave plate and a first electric turntable, the 1 / 2 wave plate is arranged on the first electric turntable, and the first electric turntable can drive the 1 / 2 wave plate to rotate along the optical axis; a 1 / 4 wave plate and a second electric turntable, the 1 / 4 wave plate is arranged on the second electric turntable, and the second electric turntable can drive the 1 / 4 wave plate to rotate along the optical axis.

[0015] Furthermore, the image rotation assembly includes an image rotation structure and a third electric turntable. The image rotation structure is arranged on the third electric turntable. The third electric turntable can drive the image rotation structure to rotate along the optical axis.

[0016] Further, the image rotation structure includes a dove prism.

[0017] Another aspect of the present invention provides an illumination system, comprising: a light source, a diffractive optical element, and a detection light modulator of any one of the above items; wherein the detection light modulator is arranged between the light source and the diffractive optical element, the illumination light emitted by the light source is modulated by the detection light modulator and the diffractive optical element in sequence to form a long strip light spot on the sample to be inspected, the illumination light emitted by the light source is modulated by the detection light modulator to form a target light beam, and along the length direction of the long strip light spot, the light intensity of the target light beam is Gaussian distributed, so that the light intensity of the long strip light spot is flat-top distributed.

[0018] Furthermore, the lighting system also includes: a circular spot sampling mirror and a circular spot monitoring camera, wherein the circular spot sampling mirror can be cut into the light path between the detection light modulation device and the diffraction optical element to guide the target light beam to the circular spot monitoring camera for imaging.

[0019] Furthermore, the lighting system also includes: a line spot sampling mirror and a line spot monitoring camera, wherein the line spot sampling mirror is used to guide the detection light emitted by the diffraction optical element to the line spot monitoring camera to image the long strip light spot.

[0020] Compared with the prior art, the invention can achieve the following beneficial effects: when the illumination light emitted by the light source changes, that is, it does not completely conform to the Gaussian distribution state, the detection light modulation device provided by the invention is used to adjust the illumination light to a target light beam, and the light spot corresponding to the target light beam adapts to the incident condition of the diffractive optical element, so that the target light beam is modulated by the diffractive optical element to form a line illumination light spot whose core parameters meet the requirements. The core parameters may include the shape and light intensity distribution state of the line illumination light spot. Even if the state of the light beam emitted by the light source changes, the core parameters of the line illumination light spot are always kept unchanged, which is beneficial to improving the uniformity and morphological consistency of the light spot of the detection light and ensuring the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A schematic diagram of the structure of the lighting system according to an embodiment of the present invention; Figure 2 A schematic diagram of different types of illumination light and their corresponding long strip light spots described in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] After analysis, it is found that the line illumination spot usually has parameter requirements on morphological distribution, external dimensions and polarization state, and the design and processing of the diffractive optical element can generally only correspond to one incident condition. When the actual incident conditions change, that is, when the incident spot does not completely conform to the Gaussian distribution state, the diffractive optical element cannot achieve the same modulation effect as the design conditions.

[0023] In order to solve the above problems, the present invention provides a detection light modulation device for being arranged in an illumination system, which can always ensure that the core parameters of the line illumination spot remain unchanged when the state of the light beam emitted by the light source changes, which is beneficial to improving the uniformity and morphology consistency of the detection light spot and ensuring the detection accuracy.

[0024] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0025] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0026] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0027] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0029] refer to Figure 1 On the one hand, the present invention provides a detection light modulation device for being arranged in an illumination system. Specifically, the detection light modulation device is used to be arranged between a light source 10 and a diffractive optical element 19. The illumination light emitted by the light source 10 is modulated by the detection light modulation device and the diffractive optical element 19 in sequence to form a long strip light spot 22 on the sample to be inspected. The purpose of the detection light modulation device provided by the present invention is to modulate the illumination light deviating from the standard into a light beam that meets the incident condition of the diffractive optical element 19. It should be noted that the incident condition of the same diffractive optical element 19 is unchanged. Only by ensuring that the light beam incident on the diffractive optical element 19 meets the incident condition of the diffractive optical element 19 can the diffractive optical element 19 form a standard long strip light spot 22 on the sample to be inspected.

[0030] In some examples, the sample to be inspected may be a wafer, and the light source 10 may include a laser.

[0031] Specifically, the illumination light emitted by the light source 10 is modulated into a target light beam by the detection light modulation device. The target light beam is a light beam that meets the incident condition of the diffractive optical element 19. The light intensity distribution of the standard long strip light spot 22 is usually a flat-top distribution. In order to diffract and obtain the standard long strip light spot 22, the target light beam needs to meet the following requirements: along the length direction of the long strip light spot 22, the light intensity of the target light beam is Gaussian distributed, so that the light intensity of the long strip light spot 22 is flat-top distributed.

[0032] In order to achieve the above-mentioned purpose, the detection light modulation device provided by the present invention at least includes an image rotation component 13. The light intensity of the illumination light is Gaussian distributed along the first preset direction. The image rotation component 13 is used to rotate the illumination light so that the first preset direction coincides with the length direction of the long strip light spot 22. That is to say, when the illumination light satisfies the Gaussian distribution of the light intensity of the illumination light along the first preset direction, but the light intensity of the illumination light does not satisfy the Gaussian distribution along the length direction of the long strip light spot 22 (also when there is an angle between the first preset direction and the length direction of the long strip light spot 22), the illumination light can be rotated by using the image rotation component 13 so that the first preset direction is rotated to coincide with the length direction of the long strip light spot 22. In other words, the illumination light (target light beam) after rotation is Gaussian distributed along the length direction of the long strip light spot 22. In this way, the light intensity of the long strip light spot 22 can be flat-top distributed along the length direction of the long strip light spot 22, which meets the requirements of the standard long strip light spot 22.

[0033] In some embodiments, the detection light modulation device further includes a variable magnification lens assembly 24, the variable magnification lens assembly 24 and the image rotation assembly 13 are arranged along the light beam transmission direction, and the variable magnification lens assembly 24 is used to adjust the size of the illumination light so that the size of the target light beam along the first preset direction is the first target size. The reason for this arrangement is that for a standard long strip light spot 22, the flat-top distribution of the light intensity of the long strip light spot 22 must satisfy: the uniformity parameter a of the light intensity is greater than the preset value. If the size of the light beam incident on the diffractive optical element 19 in the length direction of the long strip light spot 22 does not meet the requirement, the light intensity of the long strip light spot 22 formed after passing through the diffractive optical element 19 does not meet the requirement that the uniformity parameter a is greater than the preset value. In order to solve this problem, by setting the variable magnification lens assembly 24, the light beam incident on the diffractive optical element 19 is enlarged or reduced, so that the size of the target light beam along the length direction of the long strip light spot 22 meets the incident condition of the diffractive optical element 19, thereby making the uniformity parameter a of the light intensity of the long strip light spot 22 greater than the preset value.

[0034] For the standard long strip light spot 22, in some embodiments, its flat-top distribution satisfies: along the length direction of the long strip light spot 22, the uniformity parameter a of the light intensity of the long strip light spot 22 is greater than 90%, a=1-(max-min) / (max+min), wherein max is the maximum value of the light intensity of the long strip light spot 22, and min is the minimum value of the light intensity within the distribution area of ​​the long strip light spot 22.

[0035] In some embodiments, the image rotation assembly 13 and the zoom lens assembly 24 are arranged in sequence along the light beam transmission direction. It should be noted that when the illumination light emitted by the light source 10 meets the incident condition of the diffractive optical element 19, the image rotation assembly 13 and the zoom lens assembly 24 are both in zero position, that is, the detection light modulation device does not play a modulation role, the target light beam is the illumination light beam, and the transmission direction of the target light beam is consistent with the transmission direction of the illumination light beam. When the illumination light emitted by the light source 10 does not meet the incident condition of the diffractive optical element 19, the image rotation assembly 13 and the zoom lens assembly 24 may both be out of zero position to modulate the illumination light. The image rotation assembly 13 and the zoom lens assembly 24 are arranged in sequence along the light beam transmission direction, which is conducive to ensuring that the transmission direction of the target light beam formed after the illumination light is modulated by the image rotation assembly 13 and the zoom lens assembly 24 is consistent with the original optical path of the illumination light.

[0036] In some embodiments, the image rotation component 13 is also used to adjust the beam divergence angle to the target divergence angle so that the width of the long strip light spot 22 is the target width. The reason for this setting is that there may be a width requirement for the standard long strip light spot 22. For example, the width of the standard long strip light spot 22 is the first width. If the beam divergence angle of the target light beam does not meet the requirement, the width of the long strip light spot 22 formed after passing through the diffractive optical element 19 is not equal to the first width. In order to solve this problem, the beam divergence angle is adjusted by the variable magnification lens component 24 so that the beam divergence angle of the target light beam is the target divergence angle, and then a long strip light spot 22 of the first width can be formed. It should be noted that the target divergence angle is determined according to the first width, and the embodiment of the present invention does not limit the target divergence angle and the first width.

[0037] In some embodiments, the zoom lens group includes a plurality of concave-convex lenses, and the spacing between any two adjacent concave-convex lenses is adjustable. By adjusting the spacing, two functions can be achieved: one is that the light beam can be scaled within a certain range, and the other is that the divergence angle of the transmitted light beam can be controlled within a certain range.

[0038] In some embodiments, the zoom lens group includes three meniscus lenses, which are a first meniscus lens 14 , a second meniscus lens 15 , and a third meniscus lens 16 .

[0039] In some embodiments, the detection light modulation device further includes a polarization adjustment component 23, which is located between the image rotation component 13 and the light source 10, and is used to adjust the polarization direction of the illumination light so that the polarization direction of the target light beam is the target polarization direction.

[0040] In some embodiments, the polarization adjustment component 23, the image rotation component 13 and the zoom lens component 24 are sequentially arranged along the beam transmission direction. In other embodiments, the polarization adjustment component 23, the zoom lens component 24 and the image rotation component 13 are sequentially arranged along the beam transmission direction.

[0041] In some embodiments, the polarization adjustment component 23 includes a plurality of rotatable wave plates arranged along the optical path.

[0042] In some embodiments, the polarization adjustment component 23 includes: a 1 / 2 wave plate 11 and a first electric turntable, the 1 / 2 wave plate 11 is arranged on the first electric turntable, and the first electric turntable can drive the 1 / 2 wave plate 11 to rotate along the optical axis; a 1 / 4 wave plate 12 and a second electric turntable, the 1 / 4 wave plate 12 is arranged on the second electric turntable, and the second electric turntable can drive the 1 / 4 wave plate 12 to rotate along the optical axis.

[0043] It should be noted that the arrangement order of the rotatable 1 / 2 wave plate 11 and the rotatable 1 / 4 wave plate 12 can be that the 1 / 2 wave plate 11 is located between the 1 / 4 wave plate 12 and the light source 10, or that the 1 / 4 wave plate is located between the 1 / 2 wave plate and the light source 10.

[0044] In some embodiments, the image rotation assembly 13 includes an image rotation structure and a third electric turntable. The image rotation structure is disposed on the third electric turntable. The third electric turntable can drive the image rotation structure to rotate along the optical axis.

[0045] It should be noted that the optical axis in the present invention refers to the optical axis of the illumination light.

[0046] In some embodiments, the image rotation structure includes a dove prism.

[0047] The relationship between the illumination light and the long strip light spot is described in detail below based on the detection light modulation device provided by the present invention.

[0048] refer to Figure 2 , Figure 2 (a) in the figure is the light spot (referred to as the ideal Gaussian distribution lighting spot) corresponding to the illumination light with ideal light intensity distribution (referred to as the ideal Gaussian distribution lighting light). The vertical and horizontal intensity distributions of the ideal Gaussian distribution lighting spot are both standard Gaussian distributions.

[0049] For the detection light modulation device provided by the present invention, when the light spot corresponding to the illumination light is an ideal Gaussian distribution illumination spot whose polarization direction meets the requirements, the polarization adjustment component 23 is in the zero position, that is, the polarization adjustment component 23 does not change the polarization direction of the transmitted light beam, and the image rotation structure is also in the zero position, that is, it does not change the rotation direction of the transmitted light beam. If the size of the ideal Gaussian distribution illumination spot also meets the requirements, the zoom lens group is also in the zero position, that is, the size of the ideal Gaussian distribution illumination spot is not adjusted. It can be understood that if the size of the ideal Gaussian distribution illumination spot does not meet the requirements, it is necessary to use the zoom lens group to adjust the size of the ideal Gaussian distribution illumination spot to a spot size that meets the incident condition of the diffraction optical element 19, so that the light intensity distribution and size of the target light beam obtained by the detection light modulation device are consistent with the incident condition of the diffraction optical element 19, so that the target light beam can obtain the ideal after passing through the diffraction optical element 19. Figure 2 The standard line illumination spot is shown in (d).

[0050] According to the aforementioned embodiments, in some embodiments, the uniformity parameter a of the light intensity of the standard long strip light spot 22 can be greater than 90%, and the uniformity distribution of the light intensity of the long strip light spot 22 depends on the distribution state of the light intensity of the light beam incident on the diffractive optical element 19 in the vertical direction, and the size of the light beam incident on the diffractive optical element 19 in the vertical direction. The vertical direction here is the length direction of the long strip light spot 22. In addition, the design target value of the lateral width of the standard long strip light spot 22 is also a constant.

[0051] Figure 2 In the chart, the darker the color, the stronger the intensity. Figure 2 The light intensity of the long strip light spot 22 shown in (e) is strong in the middle and weak at both ends. Figure 2 The color corresponding to the light intensity of the long strip light spot 22 shown in (d) can remain basically unchanged in the illumination area, indicating that the light spot has good uniformity and is distributed in a flat top.

[0052] When the lighting changes, such as Figure 2 As shown in (b) in FIG. 1 , the spot size corresponding to the illumination light is reduced, and the intensity distribution in the vertical and horizontal directions deviates from the standard Gaussian distribution. If the polarization adjustment component 23 is at zero position, the image rotation structure is also at zero position, and the zoom lens group is also at zero position, that is, the detection light modulation device does not change the polarization direction of the transmitted light beam, does not change the rotation direction of the light beam, and maintains the original magnification. At this time, the light intensity distribution and size of the spot incident on the diffractive optical element deviate from the incident condition of the diffractive optical element 19, as shown in FIG. Figure 2As shown in (e), after passing through the diffractive optical element 19, the intensity of the obtained long strip light spot 22 is abnormally distributed in the length direction of the long strip light spot 22, and the uniformity parameter a of the light intensity is small. The lateral width of the long strip light spot 22 also deviates from the design target value of the lateral width. The long strip light spot 22 cannot meet the standard, and thus cannot achieve ideal lighting conditions for the sample to be inspected.

[0053] refer to Figure 2 (c) and Figure 2 In (f), if the detection light modulation device provided by the present invention is used, a Dove prism (or other image rotation structure) is used to rotate the direction of the illumination light, and the direction in which the intensity conforms to the Gaussian distribution is rotated to the vertical direction to align with the length direction of the long strip light spot 22. After the direction is aligned, the magnification is adjusted according to the size of the light spot in the vertical direction by using the variable magnification lens assembly 24, so that the size of the exit light spot in the vertical direction meets the incident condition of the diffractive optical element 19, forming the following Figure 2 The light spot shown in (c) in FIG. 1 is formed after the light beam passes through the diffractive optical element 19. Figure 2 The strip light spot 22 shown in (f) has a uniformity parameter a of light intensity greater than 90%. In addition, the lateral width of the strip light spot 22 can be controlled by adjusting the beam divergence angle to the designed target divergence angle through a variable magnification lens assembly.

[0054] In some embodiments, during the dark-field optical inspection of wafers, when faced with wafers with different types of defects or different materials, the polarization state of the detection light needs to be configured and switched. The detection light carrying polarization information is scattered by the surface of the sample to be inspected, processed by the imaging system, and enters the detection camera for signal collection and analysis. Therefore, the present invention uses a polarization adjustment component 23 to precisely control the polarization state of the detection light to achieve the configuration and switching of the polarization state of the detection light.

[0055] In some embodiments, when the image rotation component 13 is enabled, as the direction of the light beam rotates, the polarization direction of the light beam also changes. In order to control the polarization direction to remain unchanged, polarization rotation compensation can be performed through the polarization adjustment component 23 to ensure that the polarization state of the light beam does not change significantly after the image rotation component 13 is enabled.

[0056] In some embodiments, the state of the light beam entering the image rotation component 13 is controlled to be a linear polarization state by the polarization adjustment component 23. The benefits of adjusting to a linear polarization state include: the linear polarization state is the polarization state mainly used in dark field detection; the linear polarization state has a certain output result when used in conjunction with the polarization analyzer module, and this combination is an important part in dark field detection; the linear polarization state can be easily converted into other polarization states through a certain wave plate combination when necessary.

[0057] On the other hand, the present invention provides an illumination system, comprising: a light source 10, a diffractive optical element 19 and a detection light modulator of any one of the above items; wherein the detection light modulator is arranged between the light source 10 and the diffractive optical element 19, and the illumination light emitted by the light source 10 is modulated by the detection light modulator and the diffractive optical element 19 in sequence to form a long strip light spot 22 on the sample to be inspected, and the illumination light emitted by the light source 10 is modulated by the detection light modulator to form a target light beam, and along the length direction of the long strip light spot 22, the light intensity of the target light beam is Gaussian distributed, so that the light intensity of the long strip light spot 22 is flat-top distributed.

[0058] It should be noted that, for the detection light modulation device, the specific contents can be referred to the aforementioned embodiments, and will not be elaborated here.

[0059] In some embodiments, the lighting system further includes: a circular spot sampling mirror 17 and a circular spot monitoring camera 18, wherein the circular spot sampling mirror 17 can be inserted into the optical path between the detection light modulation device and the diffractive optical element 19 to guide the target light beam to the circular spot monitoring camera 18 for imaging. The circular spot monitoring camera 18 is used to monitor the spot morphology of the target light beam modulated by the detection light modulation device in real time. The circular spot sampling mirror 17 can collect the light beam by using a lens leakage or a sampling mirror, such as Figure 1 As shown, the circular spot sampling mirror 17 is located before the diffractive optical element 19 and can accurately reflect the distribution of the light beam entering the diffractive optical element 19.

[0060] In some embodiments, the lighting system further includes: a line spot sampling mirror 21 and a line spot monitoring camera 20, wherein the line spot sampling mirror 21 is used to guide the detection light emitted by the diffractive optical element 19 to the line spot monitoring camera 20 to image the long strip light spot 22. The line spot monitoring camera 20 can be used to monitor the morphology of the long strip light spot 22 formed by the diffractive optical element 19 in real time. The line spot sampling mirror 21 is located behind the diffractive optical element 19, and the collection position of the line spot monitoring camera 20 is equivalent to the actual illumination position of the long strip light spot 22, thereby being able to accurately reflect the morphology of the long strip light spot 22.

[0061] By adopting the lighting system provided by the present invention, it is possible to uniformly convert illumination lights of different shapes into standard long light spots 22 that meet the requirements without replacing the light source 10 and the diffractive optical element 19. Specifically, a detection light modulation device is used to adjust the non-ideal illumination light emitted by the light source 10 to a target light beam that is adapted to the incident condition of the diffractive optical element 19. When the illumination light changes, the detection light modulation device is used to keep the core parameters of the long light spot 22 modulated by the diffractive optical element 19 unchanged, which is beneficial to improving the stability of the detection light.

[0062] 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 disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0063] 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. A detection light modulation device, characterized in that: include: The detection light modulation device is used to be arranged between the light source and the diffractive optical element, and the illumination light emitted by the light source is modulated by the detection light modulation device and the diffractive optical element in sequence to form a long strip light spot on the sample to be tested; The illumination light emitted by the light source is modulated into a target light beam by the detection light modulation device, and the light intensity of the target light beam is Gaussian distributed along the length direction of the long strip light spot, so that the light intensity of the long strip light spot is flat-top distributed; The detection light modulation device at least includes an image rotation component. Along a first preset direction, the light intensity of the illumination light presents a Gaussian distribution. The image rotation component is used to rotate the illumination light so that the first preset direction coincides with the length direction of the long strip light spot.

2. The detection light modulation device according to claim 1, characterized in that: The detection light modulation device also includes a variable magnification lens assembly, and the variable magnification lens assembly and the image rotation assembly are arranged along the light beam transmission direction. The variable magnification lens assembly is used to adjust the size of the illumination light so that along the first preset direction, the size of the target light beam is a first target size.

3. The detection light modulation device according to claim 2, characterized in that: The image rotation assembly and the variable magnification lens assembly are arranged in sequence along the light beam transmission direction.

4. The detection light modulation device according to claim 2, characterized in that: The image rotation component is also used to adjust the light beam divergence angle to a target divergence angle so that the width of the long strip light spot is the target width.

5. The detection light modulation device according to claim 2, characterized in that: The variable power lens group includes a plurality of concave-convex lenses, and the distance between any two adjacent concave-convex lenses is adjustable.

6. The detection light modulation device according to claim 5, characterized in that: The variable power lens group includes three concave-convex lenses.

7. The detection light modulation device according to claim 1, characterized in that: Along the length direction of the long strip light spot, the uniformity parameter a of the light intensity of the long strip light spot is greater than 90%, a=1-(max-min) / (max+min), wherein max is the maximum value of the light intensity of the long strip light spot, and min is the minimum value of the light intensity within the distribution area of ​​the long strip light spot.

8. The detection light modulation device according to any one of claims 1 to 6, characterized in that: The detection light modulation device further comprises a polarization adjustment component, which is located between the image rotation component and the light source, and is used to adjust the polarization direction of the illumination light so that the polarization direction of the target light beam is the target polarization direction.

9. The detection light modulation device according to claim 8, characterized in that: The polarization adjustment component includes a plurality of rotatable wave plates arranged along the optical path direction.

10. The detection light modulation device according to claim 9, characterized in that: The polarization adjustment component comprises: A 1 / 2 wave plate and a first electric turntable, wherein the 1 / 2 wave plate is arranged on the first electric turntable, and the first electric turntable can drive the 1 / 2 wave plate to rotate along the optical axis; The 1 / 4 wave plate is on the second electric turntable, and the 1 / 4 wave plate is arranged on the second electric turntable, and the second electric turntable can drive the 1 / 4 wave plate to rotate along the optical axis.

11. The detection light modulation device according to claim 1, characterized in that: The image rotation assembly comprises an image rotation structure and a third electric turntable. The image rotation structure is arranged on the third electric turntable. The third electric turntable can drive the image rotation structure to rotate along the optical axis.

12. The detection light modulation device according to claim 11, characterized in that: The image rotation structure includes a Dove prism.

13. A lighting system, characterized in that: include: A light source, a diffractive optical element, and a detection light modulation device according to any one of claims 1 to 12; Among them, the detection light modulation device is arranged between the light source and the diffractive optical element, the illumination light emitted by the light source is modulated by the detection light modulation device and the diffractive optical element in sequence to form a long strip light spot on the sample to be inspected, the illumination light emitted by the light source is modulated by the detection light modulation device to form a target light beam, and along the length direction of the long strip light spot, the light intensity of the target light beam is Gaussian distributed, so that the light intensity of the long strip light spot is flat-top distributed.

14. The lighting system according to claim 13, characterized in that The illumination system further comprises: a circular spot sampling mirror and a circular spot monitoring camera, wherein the circular spot sampling mirror can be inserted into the optical path between the detection light modulation device and the diffraction optical element to guide the target light beam to the circular spot monitoring camera for imaging.

15. The lighting system according to claim 13, characterized in that The lighting system further includes: a line spot sampling mirror and a line spot monitoring camera, wherein the line spot sampling mirror is used to guide the detection light emitted by the diffraction optical element to the line spot monitoring camera to image the long strip light spot.

Images