A fixing device for an ellipsoidal mirror

Abstract

The application provides a fixing device of an ellipsoidal mirror, which is applied to the field of photoetching machines. The fixing device is provided with a clamping structure with a first circular ring column boss at the bottom of the ellipsoidal mirror, so that some positions of the outer side surface of the small opening end surface of the ellipsoidal mirror serve as elastic supporting points of the ellipsoidal mirror, and the clamping stress of the ellipsoidal mirror and the mirror surface deformation are reduced. Meanwhile, a plurality of cutting grooves are arranged on the first circular ring column in the clamping structure provided in the embodiment of the application, so that the radial rigidity of the clamping structure can be effectively reduced, and the free expansion of the ellipsoidal mirror due to heat in the exposure process is provided with space, and the thermal stress and the assembly stress of the ellipsoidal mirror are weakened, and the risk of the fragmentation of the ellipsoidal mirror is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoetching machine, in particular to a fixing device of ellipsoidal mirror. BACKGROUND

[0002] In the process of manufacturing integrated circuit, a complete chip usually needs to be manufactured through multiple exposures. In the exposure operation, the workpiece table carries the exposure object (for example, wafer), and the optical measurement system is usually arranged above the workpiece table. The mask plate is placed between the workpiece table and the optical measurement system. Through the observation and measurement of the optical measurement system, the data is transmitted to the control system, and then the control system moves the workpiece table to align the mask plate with the predetermined region of the exposure object on the workpiece table. After alignment, the exposure is started.

[0003] In the optical measurement system, the ellipsoidal mirror is an important part, and the main function is focusing. The ellipsoidal mirror is also called ellipsoidal surface mirror, and its characteristics are that the light emitted or passing through any one focus point is converged to another focus point after the ellipsoidal mirror.

[0004] Figure 1 It is a structure diagram of a fixing device of an ellipsoidal mirror in the prior art. In the fixing device of the ellipsoidal mirror shown in the figure, the positioning base ring column boss 2 with the base 1 is matched with the small hole at the bottom of the ellipsoidal mirror 5, and the top of the ellipsoidal mirror 5 adopts multiple pressing pieces 3, 4, and the multiple pressing pieces 3, 4 are uniformly distributed at the large hole end of the ellipsoidal mirror 5. Figure 1 In the fixing device of the ellipsoidal mirror shown in the figure, the positioning base ring column boss 2 with the base 1 is matched with the small hole at the bottom of the ellipsoidal mirror 5, and the top of the ellipsoidal mirror 5 adopts multiple pressing pieces 3, 4, and the multiple pressing pieces 3, 4 are uniformly distributed at the large hole end of the ellipsoidal mirror 5. Figure 1 In the fixing device of the ellipsoidal mirror shown in the figure, the positioning base ring column boss 2 with the base 1 is matched with the small hole at the bottom of the ellipsoidal mirror 5, and the top of the ellipsoidal mirror 5 adopts multiple pressing pieces 3, 4, and the multiple pressing pieces 3, 4 are uniformly distributed at the large hole end of the ellipsoidal mirror 5.

[0005] Figure 2 It is a structure diagram of another fixing device of an ellipsoidal mirror in the prior art. In the fixing device of the ellipsoidal mirror shown in the figure, the ellipsoidal mirror 9 fixing installation device adopts the large opening end face to fix the ellipsoidal mirror 9, specifically, three elastic supports 8 are used to fix and clamp the ellipsoidal mirror 9 near the large opening end face of the ellipsoidal mirror 9, and the ellipsoidal mirror seat 6 is fixedly connected with the mounting plate 7 through the inner hexagonal cylindrical head screw. Figure 2 In the fixing device of the ellipsoidal mirror shown in the figure, the ellipsoidal mirror 9 fixing installation device adopts the large opening end face to fix the ellipsoidal mirror 9, specifically, three elastic supports 8 are used to fix and clamp the ellipsoidal mirror 9 near the large opening end face of the ellipsoidal mirror 9, and the ellipsoidal mirror seat 6 is fixedly connected with the mounting plate 7 through the inner hexagonal cylindrical head screw. Figure 2 In the fixing device of the ellipsoidal mirror shown in the figure, the ellipsoidal mirror 9 fixing installation device adopts the large opening end face to fix the ellipsoidal mirror 9, specifically, three elastic supports 8 are used to fix and clamp the ellipsoidal mirror 9 near the large opening end face of the ellipsoidal mirror 9, and the ellipsoidal mirror seat 6 is fixedly connected with the mounting plate 7 through the inner hexagonal cylindrical head screw.

[0006] Figure 3 It is a structure diagram of another fixing device of an ellipsoidal mirror in the prior art. In the fixing device of the ellipsoidal mirror shown in the figure, the ellipsoidal mirror 9 fixing installation device adopts the large opening end face to fix the ellipsoidal mirror 9, specifically, three elastic supports 8 are used to fix and clamp the ellipsoidal mirror 9 near the large opening end face of the ellipsoidal mirror 9, and the ellipsoidal mirror seat 6 is fixedly connected with the mounting plate 7 through the inner hexagonal cylindrical head screw. Figure 3The fixing device of the ellipsoidal mirror shown is fixed by dispensing, specifically, one mirror support 10 is installed on each side of the large end face of the ellipsoidal mirror 11, and the gap between the ellipsoidal mirror 11 and the mirror support 12 is circularly dispensed with glue 12 to fix the ellipsoidal mirror 11. Since the ellipsoidal mirror 11 needs to be irradiated by the light source during the working process, the temperature of the ellipsoidal mirror 11 will inevitably rise, which will cause thermal deformation. Since the positioning and mounting structure and the mounting method of the ellipsoidal mirror 11 are connected to the mirror support 12 only by adhesion, once the temperature rises and the glue melts, the ellipsoidal mirror 11 deforms, and the positioning accuracy will be greatly affected.

[0007] Therefore, in view of the above problems, how to improve the horizontal positioning accuracy of the ellipsoidal mirror while reducing the clamping stress and mirror deformation of the ellipsoidal mirror, and reducing the thermal stress and assembly stress of the ellipsoidal mirror has become a problem to be solved in the field of lithography machines. SUMMARY

[0008] The purpose of the present application is to provide a fixing device of an ellipsoidal mirror to reduce the risk of fragmentation of the ellipsoidal mirror while reducing the clamping stress and mirror deformation of the ellipsoidal mirror.

[0009] To solve the above technical problems, the present application provides a fixing device of an ellipsoidal mirror, which comprises a clamping structure configured on the bottom of the ellipsoidal mirror, the clamping structure comprising a first circular column and a first circular column boss provided on the end face of the first circular column, the first circular column boss being used to contact the outer side of the small end face of the ellipsoidal mirror, and a plurality of cut grooves being provided on the first circular column.

[0010] Optionally, the contact point of the first circular column boss and the outer side of the bottom of the ellipsoidal mirror is the curved surface support point of the ellipsoidal mirror.

[0011] Optionally, the tangent line of the curved surface support point of the ellipsoidal mirror and the vertical plane of the central axis of the ellipsoidal mirror form an angle, and the angle changes with the change of the parameter of the elliptical equation of the curved surface of the ellipsoidal mirror.

[0012] Optionally, the angle formed by the tangent line of the curved surface support point of the ellipsoidal mirror and the vertical plane of the central axis of the ellipsoidal mirror can be 25°-35°.

[0013] Optionally, the cut grooves can include first cut grooves, and the first cut grooves can be strip-shaped cut grooves extending in the axial direction of the first circular column.

[0014] Optionally, the number of the first cut grooves is a plurality, and the plurality of first cut grooves are uniformly arranged in the circumferential direction of the first circular column.

[0015] Optionally, the groove includes a second groove, which is an annular groove extending along the circumferential direction of the first annular cylinder.

[0016] Optionally, there can be multiple second grooves, which are arranged in multiple rings. The second grooves in the same ring are evenly distributed, and the second grooves in adjacent rings are staggered.

[0017] Optionally, the clamping structure may further include a support base plate connected to the first annular column, and the support base plate may be provided with a third groove, which may be an annular groove extending along the circumferential direction of the first annular column.

[0018] Optionally, there may be multiple third grooves, which are arranged in multiple rings. The third grooves in the same ring are evenly distributed, and the third grooves in adjacent rings are staggered.

[0019] Optionally, the fixing device for the ellipsoidal reflector may further include a positioning structure disposed on the top of the ellipsoidal reflector, and a protective structure disposed between the positioning structure and the clamping structure for fixing the positioning structure and the clamping structure.

[0020] Optionally, the protective structure is connected to the positioning structure by screws, and at least three connection points are evenly distributed along the circumferential direction of the positioning structure; the protective structure is connected to the support base plate of the clamping structure by screws, and at least three connection points are evenly distributed along the circumferential direction of the support base plate.

[0021] Optionally, the positioning structure may include a positioning ring for positioning the large-aperture end face of the ellipsoidal reflector, and a second annular post for fixing the positioning ring.

[0022] Optionally, the positioning ring may be provided with at least three second annular column bosses along the direction toward the large opening end face of the ellipsoidal reflector.

[0023] Optionally, the lower surfaces of each of the second annular cylindrical bosses are located on the same horizontal plane and are parallel to the support base plate of the clamping structure.

[0024] Optionally, the inner diameter of the second annular cylinder can be larger than the outer diameter of the large-aperture end face of the ellipsoidal reflector, so that there is a gap between the outer edge of the large-aperture end face of the ellipsoidal reflector and the inner wall of the second annular cylinder.

[0025] Based on the same inventive concept, the present invention also provides an optical measurement system, including an ellipsoidal reflector and a fixing device for the ellipsoidal reflector as described above.

[0026] Based on the same inventive concept, the present invention also provides a lithography machine, including the optical measurement system described above.

[0027] Compared with the prior art, the technical solution of the present invention has at least one of the following beneficial effects:

[0028] In the fixing device for the ellipsoidal reflector provided by the present invention, a clamping structure with a first annular cylindrical boss is provided at the bottom of the ellipsoidal reflector, thereby enabling certain positions on the outer surface of the bottom of the ellipsoidal reflector to serve as elastic support points for the ellipsoidal reflector, thus reducing the clamping stress and mirror deformation of the ellipsoidal reflector. Simultaneously, the several grooves provided on the first annular cylinder in the clamping structure provided in the embodiment of the present invention can effectively reduce the radial stiffness of the clamping structure, thereby providing space for the free expansion of the ellipsoidal reflector due to heat during exposure, thus reducing the thermal stress and assembly stress of the ellipsoidal reflector and lowering the risk of the ellipsoidal reflector breaking.

[0029] Furthermore, in the fixing device for the ellipsoidal reflector provided by the present invention, by utilizing the horizontal characteristics of the second annular cylindrical boss in the positioning structure, the second annular cylindrical boss in the positioning structure located on the large-aperture end face of the ellipsoidal reflector is used as the positioning reference surface of the large-aperture end face of the ellipsoidal reflector, thereby ensuring the horizontal positioning accuracy of the ellipsoidal reflector while ensuring the optical performance of the ellipsoidal reflector.

[0030] In addition, the fixing device for the ellipsoidal reflector provided by the present invention does not require adhesive dispensing for support, nor does it require a specially customized ellipsoidal reflector. Standard parts can be used for the selection of the ellipsoidal reflector, thereby eliminating the risk of adhesive contamination to the entire photolithography illumination system. Therefore, the processing difficulty and procurement cost of the ellipsoidal reflector are reduced. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a fixing device for an ellipsoidal reflector in the prior art;

[0032] Figure 2 This is a schematic diagram of the structure of another ellipsoidal reflector fixing device in the prior art;

[0033] Figure 3 This is a schematic diagram of the structure of another ellipsoidal reflector fixing device in the prior art;

[0034] Figure 4 This is a front cross-sectional view of the fixing device for the ellipsoidal reflector provided in one embodiment of the present invention;

[0035] Figure 5 for Figure 4 A bottom view of the corresponding fixing device structural schematic diagram;

[0036] Figure 6 This is a schematic diagram of the solid-state device for an ellipsoidal reflector provided in one embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the clamping structure of the solid device for the ellipsoidal reflector provided in one embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the inverted positioning structure of the solid device for the ellipsoidal reflector provided in one embodiment of the present invention;

[0039] Figure 9 for Figure 8 The inverted front sectional view corresponding to the positioning structure. Detailed Implementation

[0040] As described in the background section, in the existing ellipsoidal reflector fixing devices, the following methods are typically used: Figure 1 The positioning base with a cylindrical boss 2 and a base 1 shown engages with a small hole at the bottom of the ellipsoidal reflector 5. Multiple pressure plates 3 and 4 are evenly distributed at the end of the large hole on the top of the ellipsoidal reflector 5 to fix it in place. Alternatively, the following method can be used... Figure 2 and Figure 3 The diagram shows a fixing device installed on the outer side of the large-aperture end face of the ellipsoidal reflector to fix it in place. Clearly, none of the fixing structures described above can effectively reduce the clamping stress and mirror deformation of the ellipsoidal reflector, or alleviate its thermal and assembly stresses, while simultaneously improving its horizontal positioning accuracy.

[0041] However, the inventors of this application have discovered that, under the same conditions, selecting a portion of the outer side of the small-aperture end face of the ellipsoidal reflector as the support point for the fixing device to clamp and support the ellipsoidal reflector can effectively reduce the clamping stress of the fixing device on the ellipsoidal reflector while reducing the mirror surface deformation of the ellipsoidal reflector. Specifically, for example, as... Figure 4As shown: Support point a1 is selected at the outer side of the small aperture of the ellipsoidal reflector with a radial diameter of 130 mm; support point a2 is selected at the waist of the ellipsoidal reflector with a radial diameter of 260 mm; and support point a3 is selected at the outer side of the large aperture of the ellipsoidal reflector with a radial diameter of 360 mm. Ansys software simulation was used to calculate the influence of different support point positions on the stress and surface deformation of the ellipsoidal reflector. The results show that when the ellipsoidal reflector provides the same support force, for example, 30 N, the maximum stresses at support points a1, a2, and a3 are 1.13 MPa, 1.69 MPa, and 3.47 MPa, respectively; and the maximum deformations of the ellipsoidal reflector at the three different support points are 0.00125 mm, 0.00184 mm, and 0.00366 mm, respectively.

[0042] Obviously, the clamping stress on the ellipsoidal reflector by the fixing device and the mirror deformation caused by the clamping stress are both related to the selection of the position of the support point of the fixing device that supports the ellipsoidal reflector. That is, the closer the position of the support point of the fixing device that supports the ellipsoidal reflector is to the outer edge of the small end face of the bottom of the ellipsoidal reflector, the smaller the clamping stress on the ellipsoidal reflector and the smaller the mirror deformation caused by the clamping stress.

[0043] It should be noted that the inventors of this application have also discovered that the size of the ellipsoidal mirror in the optical measurement system varies depending on the optical requirements of different exposure chips, and the size of the ellipsoidal mirror is mainly determined by the parameters in its inner surface ellipse equation (as shown in Formula 1). Therefore, the position of the support point of the fixing device for the ellipsoidal mirror is also related to the size of the ellipsoidal mirror. That is, the clamping stress of the fixing device on the ellipsoidal mirror and the position of the support point where the mirror deformation decreases due to the clamping stress will vary with the size of the ellipsoidal mirror.

[0044] Specifically, the equation formula for the inner surface ellipse of an ellipsoidal reflector is as follows:

[0045] Formula 1: x 2 / a 2 +y 2 / b 2 =1

[0046] Where a and b are parameters, and x and y are variables.

[0047] Based on this, the present invention provides a fixing device for an ellipsoidal reflector, which reduces the clamping stress and mirror deformation of the ellipsoidal reflector while reducing the risk of the ellipsoidal reflector breaking.

[0048] The following will provide a more detailed description of a fixing device for an ellipsoidal reflector according to the present invention. Refer to the accompanying drawings below.Figure 4 To be continued Figure 8 The present invention will be described in more detail below, with preferred embodiments shown. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0049] Please refer to Figures 4 to 6 , Figure 4 This is a front cross-sectional view of the fixing device for the ellipsoidal reflector provided in one embodiment of the present invention. Figure 5 for Figure 4 The bottom view of the corresponding fixing device structure diagram. Figure 6 This is a schematic diagram of the structure of the fixing device for the ellipsoidal reflector in an embodiment of the present invention.

[0050] like Figure 4 As shown, the fixing device for the ellipsoidal reflector includes a clamping structure 1' disposed at the bottom of the ellipsoidal reflector 3', a positioning structure 4' disposed at the top of the ellipsoidal reflector 3', and a protective structure 2' for fixing the positioning structure 4' and the clamping structure 1' and located between the positioning structure 4' and the clamping structure 1'. The protective structure 2' includes a fixing base plate 201, a protective cover 202, and a top mounting plate 203.

[0051] like Figure 5 As shown, and also refer to Figure 4 The fixed base plate 201 is connected to the clamping structure 1' by screws, and at least three connection points are evenly distributed along the circumferential direction of the bottom of the clamping structure 1'. Each connection point may include one screw hole 5' (or mounting hole). The top mounting plate 203 of the protective structure 2' is connected to the positioning structure 4' by screws, and at least three connection points are evenly distributed along the circumferential direction of the positioning structure 4'. Each connection point may include two screw holes 5' (or mounting holes). The screws may be hex socket head cap screws.

[0052] like Figure 6 As shown, each screw hole 5' at each connection point uses an internal hexagon head screw and a flat washer 6' to fix the protective structure 2' to the positioning structure 4' and the clamping structure 1' respectively. Since the fixing of each structure in the fixing device in this embodiment of the invention uses screw connections, the assembly of the ellipsoidal reflector is freed from adhesive application and other related steps, saving processes, avoiding the risk of adhesive contamination, and ultimately improving the positioning accuracy of the ellipsoidal reflector.

[0053] To make the description clearer, the structure of clamping structure 1' will be specifically described below through the following embodiments.

[0054] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the clamping structure 1' of the solid-state device for an ellipsoidal reflector provided in one embodiment of the present invention. Figure 7 As shown, the clamping structure 1' includes a first annular post 12 and a first annular post boss 11 disposed on the end face of the first annular post 12. The first annular post boss 11 is used to contact the outer side of the small opening end face of the ellipsoidal reflector 3'. The first annular post 12 is provided with a plurality of grooves.

[0055] In this embodiment of the invention, the contact point between the first annular cylindrical boss 11 and the outer surface of the bottom of the ellipsoidal reflector 3' is the curved surface support point of the ellipsoidal reflector 3'.

[0056] It should be noted that the size of the ellipsoidal mirror in the optical measurement system varies depending on the optical requirements of different exposure chips, and the size of the ellipsoidal mirror is mainly determined by the parameters in the equation of its inner surface ellipse. Therefore, the position of the support point of the ellipsoidal mirror clamping device is also related to the size of the ellipsoidal mirror. Specifically, the tangent of the support point on the curved surface of the ellipsoidal mirror forms a certain angle with the vertical plane of the central axis of the ellipsoidal mirror, and the angle that minimizes the maximum clamping stress at the support point varies with the parameters of the elliptical equation of the curved surface of the ellipsoidal mirror.

[0057] For example, in the elliptical equation of the ellipsoidal reflector 3' in the optical measurement system, the parameters a = 468 mm and b = 230 mm, and the small-aperture diameter of the ellipsoidal reflector 3' is generally around 90 mm. Simulation calculations show that when the radial diameter corresponding to the curved support point on the small-aperture side of the ellipsoidal reflector 3' is in the range of 110 mm to 150 mm, i.e., the angle between the tangent of the corresponding curved support point and the perpendicular plane of the central axis of the ellipsoidal reflector 3' is in the range of 25° to 35°, the maximum clamping stress of the ellipsoidal reflector 3' is less than 1.22 MPa, and the maximum deformation is less than 0.00147 mm. When the ellipsoidal reflector 3' is clamped at other surrounding points, its maximum clamping stress and maximum deformation are greater than the above values. Compared to using other surrounding points as curved support points, the maximum clamping stress and maximum deformation of the ellipsoidal reflector 3' are effectively reduced here. When the angle between the tangent of the curved support point and the vertical plane of the central axis of the ellipsoidal reflector 3' is 35°, the maximum clamping stress is minimized. Therefore, the preferred angle is 35°.

[0058] For example, in the ellipsoidal reflector 3' of the optical measurement system, the parameters a = 470 mm and b = 276 mm in the equation of the ellipse surface, and the small opening diameter of the ellipsoidal reflector 3' is generally around 120 mm. Clamping point position 1 is selected at a radial diameter of 150 mm on the ellipsoidal reflector, corresponding to a tangent angle of approximately 25° on the ellipsoidal surface; clamping point position 2 is selected at a radial diameter of 210 mm on the ellipsoidal reflector, corresponding to a tangent angle of approximately 35° on the ellipsoidal surface; and clamping point position 3 is selected at a radial diameter of 400 mm on the ellipsoidal reflector, corresponding to a tangent angle of approximately 60° on the ellipsoidal surface. Providing the same support force (30 N) for the above three cases, the maximum clamping stresses at the support points, obtained through simulation calculations, are 0.84 MPa, 0.84 MPa, and 1.43 MPa, respectively. It can be seen that when the angle between the tangent at the support point and the vertical plane of the central axis of the ellipsoidal reflector 3' is 25° to 30°, the maximum clamping stress of the ellipsoidal reflector 3' can also be effectively reduced.

[0059] In this embodiment of the invention, the groove on the first annular post 12 may include a first groove 121, which is a strip-shaped groove extending along the axial direction of the first annular post 12. Furthermore, there may be multiple first grooves 121, and all of the multiple first grooves 121 are evenly arranged along the circumferential direction of the first annular post 12.

[0060] Furthermore, in this embodiment of the invention, the groove on the first annular post 12 may further include a second groove 122, which is an annular groove extending along the circumferential direction of the first annular post 12. Moreover, there may be multiple second grooves 122, arranged in multiple rings, with the second grooves 122 in the same ring evenly distributed and the second grooves 122 in adjacent rings staggered.

[0061] For example, the second groove 122 may include an alternating first annular groove and a second annular groove, that is, the second groove 122 may be divided into two rings in the axial direction of the first annular post 12, and the same ring may contain multiple second grooves 122 evenly distributed along the circumference of the first annular post 12.

[0062] Because of the multiple grooves provided on the first annular column 12 of the clamping structure 1' provided in the embodiment of the present invention, the radial stiffness and axial thermal stress of the clamping structure 1' can be effectively reduced, thereby providing space for the free expansion of the ellipsoidal mirror due to heat during the exposure process, thus reducing the thermal stress and assembly stress of the ellipsoidal mirror and reducing the risk of the ellipsoidal mirror breaking.

[0063] In addition, see also Figure 7The clamping structure 1' further includes a support base plate 13 connected to the first annular column 12. The support base plate 13 is provided with a plurality of third grooves 131, which are annular grooves extending along the circumferential direction of the first annular column 12.

[0064] In this embodiment of the invention, the third groove 131 may include a third and fourth ring of annular grooves arranged in an alternating pattern, and multiple annular grooves in the same ring are evenly distributed along the circumferential direction of the supporting base plate 13. For example, the supporting base plate 13 is provided with two rings of annular grooves, each ring being staggered by 60 degrees, and each ring may contain three annular grooves 131. Because the layered design effectively reduces the radial stiffness of the clamping structure 1' while ensuring the axial support stiffness for the ellipsoidal reflector 3', it effectively reduces radial assembly stress.

[0065] It should be noted that, in the embodiments of the present invention, the width, elastic beam thickness, angle and number of layers of the first groove 121, the second groove 122 and the third groove 131 can be designed according to actual needs, and the present invention does not impose specific limitations on this.

[0066] To make the description clearer, the structure of positioning structure 4' will be specifically explained below through the following embodiments.

[0067] See Figure 8 and Figure 9 , Figure 8 This is a schematic diagram of the inverted positioning structure of the solid-state device for the ellipsoidal reflector provided in one embodiment of the present invention. Figure 9 for Figure 8 The inverted front sectional view corresponding to the positioning structure.

[0068] like Figure 8 As shown, and also see Figure 4 The positioning structure 4' includes a positioning ring 41 for positioning the large-aperture end face of the ellipsoidal reflector 3', and a second annular post 42 located below the positioning ring 41 for fixing the positioning ring 41. The positioning ring 41 has at least three second annular post bosses 411 along the direction towards the large-aperture end face of the ellipsoidal reflector 3'. Because... Figure 8 This is a schematic diagram of the inverted positioning structure 4'. Therefore, the positioning ring 41 and the second ring post 42 are in the opposite positions to those in actual applications.

[0069] In this embodiment of the invention, the lower surfaces of each of the second annular cylindrical bosses 411 are located on the same horizontal plane and are parallel to the support base plate 13 of the clamping structure 1'. When the positioning structure 4' is fixed to the top mounting plate 203 in the protective structure 2', they can be aligned first through their respective positioning holes 7', and then hexagonal head screws and flat washers are installed in the screw holes 5' to achieve the fixing of the positioning structure 4' to the top mounting plate 203.

[0070] Because the fixing device for the ellipsoidal reflector provided by the present invention utilizes the horizontal characteristics of the second annular cylindrical boss 411 in the positioning structure 4', the second annular cylindrical boss 411 in the positioning structure 4' located on the large opening end face of the ellipsoidal reflector 3' is used as the positioning reference surface of the large opening end face of the ellipsoidal reflector 3'. Thus, there is no need to make a separate horizontal adjustment mechanism for the ellipsoidal reflector, which can also ensure the optical performance of the ellipsoidal reflector. At the same time, it ensures the horizontal positioning accuracy of the ellipsoidal reflector, and reduces and makes controllable the horizontal adjustment amount of other optical elements relative to the ellipsoidal reflector.

[0071] In this embodiment of the invention, the inner diameter of the second annular column 42 is larger than the outer diameter of the large opening end face of the ellipsoidal reflector 3', so that a gap is left between the outer edge of the large opening end face of the ellipsoidal reflector 3' and the inner wall of the second annular column 42.

[0072] Optionally, the gap between the outer edge of the large opening end face of the ellipsoidal reflector 3' and the inner wall of the second annular column 42 can be 0.5mm to 1mm.

[0073] In this embodiment of the invention, a gap is left between the outer edge of the large opening end face of the ellipsoidal reflector 3' and the inner wall of the second annular column 42. Therefore, when the ellipsoidal reflector 3' is heated and undergoes free expansion, the gap provides space for its free expansion, thereby reducing the thermal stress of the ellipsoidal reflector and reducing the risk of the ellipsoidal reflector breaking.

[0074] Based on the ellipsoidal reflector fixing device described above, the present invention also provides an optical measurement system, including an ellipsoidal reflector 3' and the ellipsoidal reflector fixing device described above.

[0075] Furthermore, based on the ellipsoidal reflector fixing device described above, the present invention also provides a lithography machine including the optical measurement system described above.

[0076] In summary, in the ellipsoidal reflector fixing device provided by the present invention, by providing a clamping structure with a first annular cylindrical boss at the bottom of the ellipsoidal reflector, certain positions on the outer surface of the bottom of the ellipsoidal reflector serve as elastic support points, thereby reducing the clamping stress and mirror deformation of the ellipsoidal reflector. Simultaneously, the multiple grooves provided on the first annular cylinder in the clamping structure provided in the embodiments of the present invention effectively reduce the radial stiffness of the clamping structure, thus providing space for the free expansion of the ellipsoidal reflector due to heat during exposure, thereby reducing the thermal stress and assembly stress of the ellipsoidal reflector and lowering the risk of breakage.

[0077] Furthermore, in the fixing device for the ellipsoidal reflector provided by the present invention, by utilizing the horizontal characteristics of the second annular cylindrical boss in the positioning structure, the second annular cylindrical boss in the positioning structure located on the large-aperture end face of the ellipsoidal reflector is used as the positioning reference surface of the large-aperture end face of the ellipsoidal reflector, thereby ensuring the horizontal positioning accuracy of the ellipsoidal reflector while ensuring the optical performance of the ellipsoidal reflector.

[0078] In addition, the fixing device for the ellipsoidal reflector provided by the present invention does not require adhesive dispensing for support, nor does it require a specially customized ellipsoidal reflector. Standard parts can be used for the selection of the ellipsoidal reflector, thereby eliminating the risk of adhesive contamination to the entire photolithography illumination system. Therefore, the processing difficulty and procurement cost of the ellipsoidal reflector are reduced.

[0079] It should be noted that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

[0080] It should also be understood that, unless otherwise specified or indicated, the terms “first,” “second,” “third,” etc., in the specification are used only to distinguish the various components, elements, and steps in the specification, and not to indicate the logical or sequential relationships between the various components, elements, and steps.

[0081] Furthermore, it should be recognized that the terminology described herein is used only to describe particular embodiments and not to limit the scope of the invention. It must be noted that the singular forms “a” and “an” used herein and in the appended claims include plural bases unless the context clearly indicates otherwise. For example, a reference to “a step” or “an apparatus” means a reference to one or more steps or apparatuses, and may include secondary steps and secondary apparatuses. All conjunctions used should be understood in the broadest sense. Also, the word “or” should be understood to have the definition of logical “or” rather than logical “exclusive OR”, unless the context clearly indicates otherwise. Furthermore, implementation of the methods and / or apparatuses in embodiments of the invention may include performing selected tasks manually, automatically, or in combination.

Claims

1. A fixing device for an ellipsoidal reflector, characterized in that, The device includes a clamping structure for mounting on the bottom of an ellipsoidal reflector. The clamping structure includes a first annular column and a first annular column boss disposed on the end face of the first annular column. The first annular column boss is used to contact the outer side of the small-aperture end face of the ellipsoidal reflector. The first annular column is provided with a plurality of grooves. The angle between the tangent of the curved support point of the ellipsoidal reflector and the perpendicular plane of the central axis of the ellipsoidal reflector varies with the change of the elliptical equation parameters of the curved surface of the ellipsoidal reflector, and the angle is 25º~35º.

2. The fixing device for the ellipsoidal reflector as described in claim 1, characterized in that, The groove includes a first groove, which is a strip-shaped groove extending along the axial direction of the first annular column.

3. The fixing device for the ellipsoidal reflector as described in claim 2, characterized in that, There are multiple first grooves, and all of the first grooves are evenly arranged along the circumferential direction of the first annular column.

4. The fixing device for the ellipsoidal reflector as described in claim 1, characterized in that, The groove includes a second groove, which is an annular groove extending along the circumferential direction of the first annular cylinder.

5. The fixing device for the ellipsoidal reflector as described in claim 4, characterized in that, The number of the second grooves is multiple, and the multiple second grooves are arranged in multiple rings. The second grooves in the same ring are evenly distributed, and the second grooves in adjacent rings are staggered.

6. The fixing device for the ellipsoidal reflector as described in claim 1, characterized in that, The clamping structure further includes a support base plate connected to the first annular column, and the support base plate is provided with a third groove, which is an annular groove extending along the circumferential direction of the first annular column.

7. The fixing device for the ellipsoidal reflector as described in claim 6, characterized in that, The number of the third grooves is multiple, and the multiple third grooves are arranged in multiple rings. The third grooves in the same ring are evenly distributed, and the third grooves in adjacent rings are staggered.

8. The fixing device for the ellipsoidal reflector as described in claim 6, characterized in that, It also includes a positioning structure for being disposed on top of the ellipsoidal reflector, and a protective structure for fixing the positioning structure and the clamping structure and disposed between the positioning structure and the clamping structure.

9. The fixing device for the ellipsoidal reflector as described in claim 8, characterized in that, The protective structure is connected to the positioning structure by screws, and at least three connection points are evenly distributed along the circumferential direction of the positioning structure; the protective structure is connected to the support base plate of the clamping structure by screws, and at least three connection points are evenly distributed along the circumferential direction of the support base plate.

10. The fixing device for the ellipsoidal reflector as described in claim 8, characterized in that, The positioning structure includes a positioning ring for positioning the large-aperture end face of the ellipsoidal reflector, and a second annular post for fixing the positioning ring.

11. The fixing device for the ellipsoidal reflector as described in claim 10, characterized in that, The positioning ring is provided with at least three second annular column protrusions along the direction toward the large opening end face of the ellipsoidal reflector.

12. The fixing device for the ellipsoidal reflector as described in claim 11, characterized in that, The lower surfaces of each of the second annular column bosses are located on the same horizontal plane and are parallel to the support base plate of the clamping structure.

13. The fixing device for the ellipsoidal reflector as described in claim 10, characterized in that, The inner diameter of the second annular cylinder is larger than the outer diameter of the large-aperture end face of the ellipsoidal reflector, so that there is a gap between the outer edge of the large-aperture end face of the ellipsoidal reflector and the inner wall of the second annular cylinder.

14. An optical measurement system, characterized in that, It includes an ellipsoidal reflector and a fixing device for the ellipsoidal reflector as described in any one of claims 1 to 13.

15. A lithography machine, characterized in that, Includes the optical measurement system as described in claim 14.

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