Error Analysis Method for Detecting the Polarization State of Light at the Silicon Wafer in a Lithography Machine

Abstract

The present invention relates to the technical field of polarization detection, and provides an error analysis method for detecting the optical polarization state at a silicon wafer in a lithography machine. The incident angle of the light beam incident on the zero-order quarter-wave plate is determined according to the defocus amount of the coupling mirror; according to the incident angle of the light beam on the zero-order quarter-wave plate, the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate is calculated; the Stokes parameters of the light at the silicon wafer in the non-ideal element state are determined according to the wave plate phase delay; the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism are considered in the non-ideal element state; according to the Stokes parameters of the light at the silicon wafer in the non-ideal element state and the Stokes parameters of the light at the silicon wafer in the preset ideal element state, the error analysis result of the optical polarization state detection at the silicon wafer is determined. The present invention can achieve accurate error analysis of the optical polarization state detection at the silicon wafer, contribute to lithography simulation, optimize the design of the lithography machine system, and ultimately improve the lithography imaging quality.

Description

Technical Field

[0001] The present invention relates to the technical field of polarization detection, and particularly to an error analysis method for detecting the optical polarization state at a silicon wafer in a lithography machine. Background Art

[0002] With the continuous increase of the numerical aperture (NA, Numerical Aperture) of the lithography system and the decreasing of the feature size (CD, Critical Dimension) of the exposed pattern, the influence of the polarization characteristics of light on the lithography performance becomes more and more significant. The detection error of the polarization state detection system at the silicon wafer of the lithography machine is a key index to measure the detection quality. Therefore, the accurate measurement and in-depth analysis of the detection system can not only provide an important basis for lithography simulation, but also optimize the design of the lithography machine system, thus significantly improving the lithography imaging quality. Summary of the Invention

[0003] The present invention provides an error analysis method for detecting the optical polarization state at a silicon wafer in a lithography machine, which can realize accurate error analysis of the optical polarization state detection at the silicon wafer, contribute to lithography simulation, optimize the design of the lithography machine system, and ultimately improve the lithography imaging quality.

[0004] The present invention provides an error analysis method for detecting the optical polarization state at a silicon wafer in a lithography machine, which is applied to the optical polarization state detection system at the silicon wafer in the lithography machine. The detection system successively includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back; after the light beam at the silicon wafer of the lithography machine becomes parallel light through the coupling mirror, it successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device; the method includes: determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; determining the Stokes parameters of the light at the silicon wafer in the non-ideal element state according to the wave plate phase delay; the non-ideal element state considers the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism; determining the error analysis result of the optical polarization state detection at the silicon wafer according to the Stokes parameters of the light at the silicon wafer in the non-ideal element state and the Stokes parameters of the light at the silicon wafer in the preset ideal element state.

[0005] An error analysis method for detecting the optical polarization state at the wafer in a lithography machine according to the present invention, determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror, includes: determining the object-side coordinates after defocus of the coupling mirror according to the defocus amount of the coupling mirror and the focal length of the coupling mirror; determining the image point position after defocus of the coupling mirror according to the object-side coordinates and the defocus amount; determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the clear aperture of the coupling mirror and the image point position.

[0006] An error analysis method for detecting the optical polarization state at the wafer in a lithography machine according to the present invention, the defocus amount of the coupling mirror is within the range of ±100 nm, and the light beam incident on the zero-order quarter-wave plate is a conical light beam.

[0007] An error analysis method for detecting the optical polarization state at the wafer in a lithography machine according to the present invention, before calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate, further includes: selecting the structural parameters of the zero-order quarter-wave plate; the structural parameters include the thickness of the first structural crystal and the thickness of the second structural crystal; calculating the initial phase delay of the zero-order quarter-wave plate according to the structural parameters, so as to calculate the wave plate phase delay corresponding to the alignment error based on the initial phase delay.

[0008] An error analysis method for detecting the optical polarization state at the wafer in a lithography machine according to the present invention, after determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror, further includes: calculating the wave plate phase delay corresponding to the processing error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate.

[0009] An error analysis method for detecting the optical polarization state at the wafer in a lithography machine according to the present invention, the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate is greater than the wave plate phase delay corresponding to the processing error of the zero-order quarter-wave plate.

[0010] An error analysis method for detecting the optical polarization state at the wafer in a lithography machine according to the present invention, when the wave plate phase delay caused by the defocus of the coupling mirror, the processing and alignment of the wave plate itself of the zero-order quarter-wave plate is in the range, the absolute detection error of the Stokes parameters s0 and s1 of the light at the wafer is ten percent, the absolute detection error of s2 is five percent, and the absolute detection error of s3 is five per thousand.

[0011] The present invention also provides an error analysis system for detecting the optical polarization state at the wafer in a lithography machine, which is applied to the optical polarization state detection system at the wafer in the lithography machine. The detection system sequentially includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back. After the light beam at the wafer of the lithography machine becomes parallel light through the coupling mirror, it successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device. The error analysis system includes: an incident angle determination module for determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; an alignment calculation module for calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; a parameter determination module for determining the Stokes parameters of the light at the wafer in the non-ideal element state according to the wave plate phase delay; the non-ideal element state considers the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism; an analysis result determination module for determining the error analysis result of the optical polarization state detection at the wafer according to the Stokes parameters of the light at the wafer in the non-ideal element state and the Stokes parameters of the light at the wafer in the preset ideal element state.

[0012] The present invention also provides an optical polarization state detection system at the wafer in a lithography machine, characterized in that the error analysis method for detecting the optical polarization state at the wafer in the lithography machine as described above is used for error analysis.

[0013] The present invention also provides a lithography machine, characterized in that it includes the optical polarization state detection system at the wafer in the lithography machine as described above.

[0014] An error analysis method for detecting the optical polarization state at the wafer in a lithography machine provided by the present invention determines the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; calculates the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; determines the Stokes parameters of the light at the wafer in the non-ideal element state according to the wave plate phase delay; the non-ideal element state considers the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism; determines the error analysis result of the optical polarization state detection at the wafer according to the Stokes parameters of the light at the wafer in the non-ideal element state and the Stokes parameters of the light at the wafer in the preset ideal element state. The present invention can achieve accurate error analysis of the optical polarization state detection at the wafer, contribute to lithography simulation, optimize the lithography machine system design, and ultimately improve the lithography imaging quality. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic flowchart of an error analysis method for detecting the optical polarization state at the silicon wafer in the lithography machine provided by the present invention.

[0017] Figure 2 It is a schematic diagram of the principle for measuring the optical polarization state at the silicon wafer provided by the present invention.

[0018] Figure 3 It is a diagram showing the change in the incident angle of the subsequent optical path caused by the defocus of the coupling mirror provided by the present invention.

[0019] Figure 4 It is a diagram showing the corresponding relationship between the defocus amount of the coupling mirror and the incident angle of the wave plate provided by the present invention.

[0020] Figure 5 It is provided by the present invention that when the thicknesses of the first-structured crystal and the second-structured crystal in the zero-order quarter-wave plate have processing errors, the additional phase delay diagram caused by the thickness processing errors.

[0021] Figure 6 It is provided by the present invention that when the optical axis of the first-structured crystal in the zero-order quarter-wave plate has processing errors, the additional phase delay diagram caused by the optical axis processing errors.

[0022] Figure 7 It is provided by the present invention that when the optical axis of the second-structured crystal in the zero-order quarter-wave plate has processing errors, the additional phase delay diagram caused by the optical axis processing errors.

[0023] Figure 8 It is a schematic diagram of the zero-order quarter-wave plate rotating around the x-axis provided by the present invention.

[0024] Figure 9 It is provided by the present invention that when the azimuth angle of the incident plane respectively takes , , and , the change trend diagram of the additional phase delay with the incident angle and the rotation angle around the x-axis (sub-graph a is , sub-graph b is , sub-graph c is , the d sub - figure is ).

[0025] Figure 10 is the graph of the variation range of the additional delay amount with the rotation angle around the x - axis when the incident angle provided by the present invention is changing, and at the same time, the azimuth angle of the incident plane is also taking values.

[0026] Figure 11 is the schematic diagram of the zero - order 1 / 4 wave - plate rotating around the y - axis provided by the present invention.

[0027] Figure 12 is when the azimuth angle of the incident plane provided by the present invention is respectively taking , , and , the graph of the variation trend of the additional phase - delay amount with the incident angle and the rotation angle around the y - axis (the a sub - figure is , the b sub - figure is , the c sub - figure is , the d sub - figure is ).

[0028] Figure 13 is the graph of the variation range of the additional delay amount with the rotation angle around the y - axis when the incident angle provided by the present invention is changing, and at the same time, the azimuth angle of the incident plane is also taking values.

[0029] Figure 14 is the schematic diagram of the zero - order 1 / 4 wave - plate rotating around the z - axis provided by the present invention.

[0030] Figure 15 is when the azimuth angle of the incident plane provided by the present invention is respectively taking , , and , the graph of the variation trend of the additional phase - delay amount with the incident angle and the rotation angle around the z - axis (the a sub - figure is , the b sub - figure is , the c sub - figure is , the d sub - figure is ).

[0031] Figure 16 is the graph of the variation range of the additional delay amount with the rotation angle around the z - axis when the incident angle provided by the present invention is changing, and at the same time, the azimuth angle of the incident plane is also taking values.

[0032] Figure 17 This is the error graph of each Stokes parameter caused when there is an additional phase difference in the zero-order quarter-wave plate provided by the present invention.

[0033] Figure 18 This is a schematic structural diagram of an error analysis system for detecting the light polarization state at the silicon wafer in a lithography machine provided by the present invention.

[0034] Figure 19 This is a schematic structural diagram of an electronic device provided by the present invention. Detailed implementation manners

[0035] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0036] Ultra-high numerical aperture imaging systems are widely used in immersion microscopes and immersion lithography tools. However, ultra-high NA imaging systems with large incident angles introduce significant polarization effects, seriously affecting the imaging quality. Therefore, it becomes particularly important to accurately measure and control the polarization characteristics of ultra-high NA imaging systems. Detection error is one of the important indicators reflecting the quality of measurement. The detection accuracy of a polarization measuring instrument is affected by the errors of its internal detection elements. The light polarization state detection instrument at the silicon wafer mainly consists of a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a CCD (Charge-Coupled Device). Due to various errors that may occur during detection, such as processing and alignment, of the coupling mirror and the wave plate, there is currently no error analysis method for such detection technologies.

[0037] Please refer to Figure 1 , Figure 1 This is a schematic flow diagram of an error analysis method for detecting the light polarization state at the silicon wafer in a lithography machine provided by the present invention.

[0038] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the principle for measuring the light polarization state at the silicon wafer provided by the present invention.

[0039] The present invention provides an error analysis method for detecting the light polarization state at the wafer in a lithography machine, which is applied to the light polarization state detection system at the wafer in the lithography machine. The detection system successively includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back; after the light beam at the wafer of the lithography machine is turned into parallel light by the coupling mirror, it successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device;

[0040] The method includes:

[0041] 101: Determine the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror;

[0042] 102: Calculate the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate;

[0043] 103: Determine the Stokes parameters of the light at the wafer in the non-ideal element state according to the wave plate phase delay; in the non-ideal element state, consider the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism;

[0044] 104: Determine the error analysis result of the light polarization state detection at the wafer according to the Stokes parameters of the light at the wafer in the non-ideal element state and the Stokes parameters of the light at the wafer in the preset ideal element state.

[0045] For facilitating the analysis of the influence of the errors of each element on the detection result, the present invention derives an expression of the Stokes parameters of the light at the wafer that contains both the delay characteristics of the zero-order quarter-wave plate and the bidirectional attenuation rate characteristics of the polarization prism (non-ideal element state), which provides a theoretical basis for the data processing, error analysis, and system calibration of future experiments. And specifically analyzes the influence of the defocus of the coupling mirror and the delay error of the zero-order quarter-wave plate on the light polarization state detection error at the wafer.

[0046] The detection principle of the light polarization state detector at the wafer of the lithography machine is: After the high-NA light beam at the wafer of the lithography machine is turned into parallel light by the coupling mirror, it successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the CCD. During measurement, the zero-order quarter-wave plate is rotated around the optical axis of the lithography machine system. Suppose there are N modulation points in one rotation of the wave plate, then the CCD collects an image corresponding to one modulation point. Draw a two-dimensional curve graph according to the corresponding relationship between the modulation point and the light intensity. Observe the period π of the curve graph and expand it into a Fourier series. Finally, through the relationship between the Fourier coefficients and the Stokes parameters, calculate the Stokes parameters of each point on the pupil.

[0047] When detecting the polarization state of the light beam at the wafer in a high-NA lithography system, the light to be measured is first converted into parallel light by a coupling mirror, and then passes through a rotatable zero-order quarter-wave plate and a polarization prism with a fixed azimuth angle in sequence to reach the surface of the image detector. During the measurement process, the zero-order quarter-wave plate is rotated at a certain step angle. Each time the wave plate rotates, the image sensor acquires an image. Then, Fourier analysis is performed on the image to obtain the polarization state of the light at the wafer. The characteristics of this technology are as follows: By fixing the azimuth angle of the polarization prism, the influence of the polarization selectivity of the photosensitive surface of the photodetector on the detection is effectively avoided; during the measurement, there are many sampling points, so compared with a polarization measuring instrument with only a limited number of combinations of wave plates and polarizers, the measurement accuracy of this instrument is high. The polarization state of the light beam is usually represented by Stokes parameters. For a high-NA lithography system, the Stokes parameters of the light at the wafer After passing through the coupling mirror and the zero-order wave plate And the polarization prism It is then converted into :

[0048] ,

[0049] If it is assumed that the zero-order wave plate (specifically a zero-order quarter-wave plate in this detection system) and the polarization prism are ideal elements, that is, the retardance Of the zero-order quarter-wave plate and the bidirectional attenuation rate Of the polarization prism, the Stokes parameters of the light at the wafer under the preset ideal element state are:

[0050] ,

[0051] Among them, Is the azimuth angle of the polarization prism, , , , And Are Fourier coefficients determined by the corresponding relationship between the light intensity Output by the photodetector and the azimuth angle Of the zero-order quarter-wave plate.

[0052] For the needs of high detection accuracy and error analysis in a high-NA lithography system, the present invention derives the solution process of the polarization state of the light at the wafer in the lithography system under the non-ideal element state after considering the system errors (characteristic parameters of the coupling mirror, zero-order quarter-wave plate, and polarization prism).

[0053] First, the solution process of the polarization state of the light at the wafer of the lithography machine is derived considering the characteristic parameters of the zero-order wave plate and the polarization prism. The muller matrices of the non-ideal zero-order quarter-wave plate and the polarization prism (that is, the muller matrix considering not only the azimuth angles of the wave plate and the polarization prism but also the wave plate phase retardation and the bidirectional attenuation rate characteristics of the polarization prism) are as follows:

[0054] ,

[0055] ,

[0056] wherein, is the azimuth angle of the polarization prism, is the azimuth angle of the zero-order 1 / 4 wave plate, is the bidirectional attenuation rate through the polarization prism, is the phase delay of the zero-order 1 / 4 wave plate.

[0057] If we let

[0058] ,

[0059] where

[0060] The first column elements:

[0061] ,

[0062] The second column elements:

[0063] ,

[0064] The third column elements:

[0065] ,

[0066] The fourth column elements:

[0067] .

[0068] The measurement process is to rotate the zero-order 1 / 4 wave plate around the optical axis of the entire optical system, then the relationship between the transmitted light intensity I and the Stokes parameters at the silicon wafer is:

[0069] ,

[0070] where ; is the angular velocity of the wave plate rotation. Suppose there are modulation points when the wave plate rotates one week, then the rotation step angle , . The transmitted light intensity I can be expanded in the form of Fourier series:

[0071] ,

[0072] ,

[0073] where, is the light intensity value measured at each modulation point, and

[0074] ,

[0075] is determined by the least squares method with the Stokes parameters at the silicon wafer as variables. Thus, the Stokes parameters can be obtained as:

[0076] ,

[0077] It can be seen from the above formula that in the actual measurement process, first, the light intensity curve is obtained through the corresponding relationship between each angle of rotation of the zero-order 1 / 4 wave plate and the light intensity value. Then, by performing Fourier analysis on this curve, the Stokes parameters of the light to be measured at the silicon wafer can be obtained.

[0078] The present invention analyzes the change in the incident angle of the subsequent detection optical path when the coupling mirror is defocused in this polarization state detection device. Then, due to the additional phase difference caused by the alignment and adjustment of the zero-order wave plate, specifically analyzes the phase delay change of the zero-order 1 / 4 wave plate when it rotates or tilts around a certain coordinate axis when detecting each Stokes parameter of the light to be measured at the silicon wafer in the lithography system. The wave plate error restricts the detection error of the polarization state of the light to be measured at the silicon wafer to a great extent. The present invention can achieve precise error analysis of the polarization state detection of the light at the silicon wafer, which is helpful for lithography simulation and optimization of the lithography machine system design, and ultimately improves the lithography imaging quality.

[0079] As a preferred embodiment, determining the incident angle of the beam incident on the zero-order 1 / 4 wave plate according to the defocus amount of the coupling mirror includes: determining the object-side coordinates after the defocus of the coupling mirror according to the defocus amount of the coupling mirror and the focal length of the coupling mirror; determining the image point position after the defocus of the coupling mirror according to the object-side coordinates and the defocus amount; and determining the incident angle of the beam incident on the zero-order 1 / 4 wave plate according to the clear aperture of the coupling mirror and the image point position.

[0080] As a preferred embodiment, when the defocus amount of the coupling mirror is within the range of ±100 nm, the beam incident on the zero-order 1 / 4 wave plate is a conical beam.

[0081] Please refer to Figure 3 , Figure 3 , which is the change diagram of the incident angle of the subsequent optical path caused by the defocus of the coupling mirror provided by the present invention.

[0082] Please refer to Figure 4 , Figure 4 , which is the corresponding relationship diagram between the defocus amount of the coupling mirror and the incident angle of the wave plate provided by the present invention.

[0083] The light to be measured at the silicon wafer, compared with that at the mask surface, has an incident angle range several times that of the mask surface, except that the azimuth angles of the incident surfaces are the same. The polarization elements used in this embodiment include a two-piece zero-order quarter-wave plate and a polarization prism. However, a coupling mirror needs to be added in front of these two polarization elements to convert the beam incident at a large angle into parallel light. After introducing the coupling mirror, it is necessary to analyze the influence it brings to polarization detection, such as: the defocus of the coupling mirror will cause a change in the incident angle of the subsequent optical path.

[0084] The focal length of the coupling mirror is , and the object point position and image point position are respectively and , and the defocus amount . According to the Gaussian formula

[0085] ,

[0086] and the relationship between the object-space focal length and image-space focal length of the optical system in air

[0087] ,

[0088] it can be obtained that:

[0089] .

[0090] After the coupling mirror is defocused, its object-space coordinates are:

[0091] ,

[0092] Then, after the coupling mirror is defocused, the image point position is:

[0093] .

[0094] If the clear aperture of the coupling mirror is , the incident angle formed on the surface of the subsequent polarization detection element after the coupling mirror is defocused is no longer zero, but

[0095] .

[0096] Through the above derivation, it is known that after knowing the clear aperture , focal length and defocus amount of the coupling mirror, the influence of the coupling mirror defocus on the parallelism of its outgoing beam can be obtained.

[0097] For a projection objective with NA = 1.35, when = 6.8 mm, = -5348 mm, and at When it varies within the range of 100 nm, the angle between the light beam incident on the surface of the zero-order quarter-wave plate and the normal of the wave plate surface (i.e., the incident angle of the light beam) can be obtained. and corresponding relationship.

[0098] When the coupling mirror is defocused within the range of 100 nm, the light beam emitted from it is no longer a normally incident light ray parallel to the optical axis of the system, but a conical light beam with a certain incident angle (i.e., , ).

[0099] The defocus of the coupling mirror will cause the degree of convergence or divergence of the light beam to change, thereby changing the incident angle in the subsequent optical path. The change in the incident angle will affect the phase delay characteristics of the zero-order quarter-wave plate, and further affect the detection accuracy of the polarization state. Through the above steps, the influence of the defocus of the coupling mirror on the incident angle can be accurately calculated, providing a theoretical basis for subsequent error analysis and system optimization.

[0100] As a preferred embodiment, before calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate, it further includes: selecting the structural parameters of the zero-order quarter-wave plate; the structural parameters include the thickness of the first structural crystal and the thickness of the second structural crystal; calculating the initial phase delay of the zero-order quarter-wave plate according to the structural parameters, so as to calculate the wave plate phase delay corresponding to the alignment error based on the initial phase delay.

[0101] Please refer to Figure 5 , Figure 5 which is the additional phase delay amount diagram caused by the thickness processing error when the thicknesses of the first structural crystal and the second structural crystal in the zero-order quarter-wave plate of the present invention have processing errors respectively.

[0102] Please refer to Figure 6 , Figure 6 which is the additional phase delay amount diagram caused by the optical axis processing error when the optical axis of the first structural crystal in the zero-order quarter-wave plate of the present invention has processing errors.

[0103] Please refer to Figure 7 , Figure 7 which is the additional phase delay amount diagram caused by the optical axis processing error when the optical axis of the second structural crystal in the zero-order quarter-wave plate of the present invention has processing errors.

[0104] The zero-order quarter-wave plate is an important part of the optical polarization state detection instrument at the silicon wafer. In this embodiment, the structural parameters of the zero-order quarter-wave plate are specifically designed.

[0105] The zero-order quarter-wave plate is made of a positive crystal and is usually composed of two multi-order quarter-wave plates with almost the same characteristics. When the incident light satisfies the condition of, the retardation of the multi-order quarter-wave plate is:

[0106] ,

[0107] where, and are the principal refractive indices of the positive crystal, is the thickness of the multi-order quarter-wave plate, is a positive integer, is the wavelength of the incident light.

[0108] .

[0109] In the practical application of detecting the beam polarization state at the silicon wafer in an immersion lithography machine, the zero-order quarter-wave plate is made of the positive crystal magnesium fluoride (MgF2). At = 193 nm, its principal refractive indices are = 1.441 and = 1.428. When the thickness of the magnesium fluoride quarter-wave plate is approximately at the time of selection = 13. Then the initial thickness of the first magnesium fluoride wave plate (the first structural crystal).

[0110] Adjust the thicknesses of the two magnesium fluoride crystals so that the thickness difference between the two is equal to the thickness of the single-piece zero-order quarter-wave plate, that is, . Therefore, the initial thickness of the second magnesium fluoride wave plate (the second structural crystal).

[0111] Thus, the initial thickness of the zero-order quarter-wave plate is obtained, and then the initial phase retardation of the zero-order quarter-wave plate is calculated:

[0112] .

[0113] where, the incident angle , the azimuth angle of the incident plane . The initial value of the retardation corresponding to the initial thickness is .

[0114] Then substitute the initial value of into the objective function , and obtain the difference between the initial phase retardation and the ideal phase retardation of the zero-order quarter-wave plate.

[0115] Suppose the possible variation ranges of the thickness parameters of the two crystals in the zero-order quarter-wave plate are set to

[0116] .

[0117] After that, N groups of thickness parameters are obtained. During the calculation process, step size and are used.

[0118] The global optimal thickness of the two crystals The change amount of the delay difference is effectively reduced to , which is significantly improved compared with the initial value of .

[0119] As a preferred embodiment, after determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror, it further includes: calculating the wave plate phase delay corresponding to the processing error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate.

[0120] The zero-order quarter-wave plate is an important component in the optical polarization state detection instrument at the silicon wafer. The quality of its performance directly affects the detection accuracy of the Stokes parameters of the light at the silicon wafer. And various errors may occur in this wave plate during processing or alignment in the detection process. Since two zero-order wave plates made of the same material are used when detecting the optical polarization state at the silicon wafer, it is necessary to analyze the additional phase difference caused by processing errors such as the thickness and optical axis direction of each crystal inside the zero-order wave plate.

[0121] In this embodiment, when the thickness of each piece of the zero-order quarter-wave plate changes , its phase delay amount changes to:

[0122] ,

[0123] When the thicknesses of the two pieces in the zero-order quarter-wave plate and change respectively, the change range of the additional delay amount can basically be within .

[0124] When the optical axis of each piece of the zero-order wave plate changes due to misalignment during processing, its phase delay amount changes to:

[0125] ,

[0126] When the optical axis directions of the two pieces in the zero-order quarter-wave plate change When, the variation range of the additional delay amount is .

[0127] As a preferred embodiment, the waveplate phase delay corresponding to the alignment error of the zero-order 1 / 4 waveplate is greater than the waveplate phase delay corresponding to the processing error of the zero-order 1 / 4 waveplate.

[0128] In this embodiment, the influence of the additional phase difference of the zero-order 1 / 4 waveplate on its own alignment error is specifically analyzed.

[0129] Please refer to Figure 8 , Figure 8 , which is a schematic diagram of the zero-order 1 / 4 waveplate provided by the present invention rotating around the x-axis.

[0130] Please refer to Figure 9 , Figure 9 , which is the additional phase delay amount varying with the incident angle and the rotation angle 、 、 and when the azimuth angle of the incident plane provided by the present invention takes and rotates around the x-axis (sub-graph a is , sub-graph b is , sub-graph c is , sub-graph d is ).

[0131] Please refer to Figure 10 , Figure 10 , which is a graph of the variation range of the additional delay amount with the rotation angle around the x-axis when the incident angle is changing within and the azimuth angle of the incident plane is also taking values within as provided by the present invention.

[0132] When the two-piece zero-order waveplate rotates around the x-axis, its phase delay amount changes to:

[0133] ,

[0134] wherein, is the incident angle, is the azimuth angle of the incident plane, is the rotation angle of the zero-order 1 / 4 waveplate around the x-axis.

[0135] Then when the zero-order 1 / 4 waveplate rotates around the x-axis , the induced additional phase delay is: .

[0136] When the light beam exiting from the coupling mirror forms an angle of with the waveplate interface and the waveplate rotates around the x-axis , and is symmetric about the plane of ; and is symmetric about the plane of . When the azimuth angle of the incident plane or , the additional phase difference caused by the rotation of the wave plate around the x-axis is the largest. And when varies among these four azimuth angles, the additional phase delay difference . For all incident light rays incident on the two-piece MgF2 zero-order 1 / 4 wave plate, that is, when the incident angle varies within , and the azimuth angle of the incident plane also varies within , the range of values of the additional phase delay amount with respect to the rotation of the zero-order 1 / 4 wave plate around the x-axis is .

[0137] Please refer to Figure 11 , Figure 11 which is a schematic diagram of the rotation of the zero-order 1 / 4 wave plate around the y-axis provided by the present invention.

[0138] Please refer to Figure 12 , Figure 12 which is a graph showing the variation trend of the additional phase delay amount with respect to the incident angle and the rotation angle , , and respectively when the azimuth angle of the incident plane and the rotation angle around the y-axis vary (sub-graph a is , sub-graph b is , sub-graph c is , and sub-graph d is ).

[0139] Please refer to Figure 13 , Figure 13 which is a graph showing the range of variation of the additional delay amount with respect to the rotation angle around the y-axis when the incident angle varies within and the azimuth angle of the incident plane also varies within .

[0140] When the two-piece zero-order wave plate rotates around the y-axis, its phase delay amount changes to:

[0141] ,

[0142] where is the incident angle, is the azimuth angle of the incident plane, and is the rotation angle of the zero-order 1 / 4 wave plate around the y-axis.

[0143] When the two-piece zero-order waveplate rotates about the y-axis the additional phase delay caused is: .

[0144] When the azimuth angle of the incident plane the additional phase difference caused by the waveplate rotating about the y-axis is maximum. and are exactly the same as those at When varying at these four azimuth angles, the additional phase delay difference . When the azimuth angle of the incident plane is at and the incident angle is at the additional phase delay caused by the two-piece zero-order quarter-waveplate rotating about the y-axis varies with the rotation angle . For a conical light beam within the range of the incident angle when the two-piece zero-order quarter-waveplate rotates about the y-axis its delay variable varies within the range of .

[0145] Please refer to Figure 14 , Figure 14 which is the schematic diagram of the zero-order quarter-waveplate provided by the present invention rotating about the z-axis.

[0146] Please refer to Figure 15 , Figure 15 which is the graph showing the variation trend of the additional phase delay with the incident angle and the rotation angle about the z-axis , , and respectively when the azimuth angle of the incident plane provided by the present invention takes and (sub-graph a is , sub-graph b is , sub-graph c is , sub-graph d is ).

[0147] Please refer to Figure 16 , Figure 16 which is the graph showing the variation range of the additional delay with the rotation angle about the z-axis when the incident angle provided by the present invention varies within and the azimuth angle of the incident plane also takes values within .

[0148] When the two-piece zero-order waveplate rotates about the z-axis, its phase delay changes to:

[0149] ,

[0150] where is the incident angle, is the azimuth angle of the incident plane, is the rotation angle of the zero-order 1 / 4 wave plate around the z-axis.

[0151] Then, when the two-piece zero-order wave plate rotates around the z-axis by the additional phase delay caused is: .

[0152] When the azimuth angle of the incident plane the additional phase difference caused by the rotation of the wave plate around the z-axis is the largest. The graphical change at this time is not affected by the incident angle. And when When changing among these four azimuth angles, the additional phase delay difference . The azimuth angle of the incident plane is at , the incident angle is at When taking values, the additional phase delay amount caused by the rotation of the two-piece zero-order 1 / 4 wave plate around the z-axis varies with the rotation angle . For the conical beam within the range of the incident angle when the two-piece zero-order 1 / 4 wave plate rotates around the z-axis by its delay variable varies within the range of .

[0153] From the analysis of the alignment error caused by the rotation of the above two-piece zero-order wave plate around the coordinate axes, it can be known that when the two-piece zero-order wave plate rotates around each coordinate axis by the alignment error in a single direction is .

[0154] As a preferred embodiment, when the wave plate phase delay caused by the defocusing of the coupling mirror, the processing and alignment of the wave plate itself is within the range of the absolute detection error of the Stokes parameters s0 and s1 of the light at the silicon wafer is within ten percent, the absolute detection error of s2 is within five percent, and the absolute detection error of s3 is within five per thousand.

[0155] Please refer to Figure 17 , Figure 17 is the error diagram of each Stokes parameter caused by the additional phase difference in the zero-order 1 / 4 wave plate provided by the present invention. when there is

[0156] According to the above analysis, when the defocusing amount of the coupling mirror changes within ±100 nm, the light beam emitted from it is no longer a normal incident light parallel to the optical axis of the system, but a conical beam with a certain incident angle (that is, , ). When this conical beam is superimposed with the processing error of the zero-order wave plate, the additional phase difference caused is less than , they have little impact on the detection of the light polarization state at the wafer in a high-NA lithography system. When the conical beam is superimposed with the alignment error of the zero-order waveplate rotating around the coordinate axis, the resulting additional phase difference is relatively large.

[0157] Specifically analyzing the detection of each Stokes parameter of the light to be measured at the wafer in a laboratory lithography system with NA 1.35, when the zero-order quarter-waveplate rotates or tilts around a certain coordinate axis The maximum phase delay changes of the zero-order quarter-waveplate are respectively , and ; and when the thickness processing error of the single crystal in the zero-order quarter-waveplate is or due to the misalignment error of the optical axis processing of the single crystal is , the additional phase delay of the zero-order quarter-waveplate is and . The analysis results show that when the alignment angle error of the two-piece zero-order quarter-waveplate and the optical axis processing error of the single crystal are both , the additional phase difference caused by the latter is more than twenty times smaller than that of the former. The maximum additional phase difference generated by the zero-order quarter-waveplate affected by various factors is within . If it is assumed that the Stokes parameters of the light to be measured at the wafer are , . Then substituting the additional phase difference varying within the range of of the zero-order quarter-waveplate into the Stokes parameter formula, the deviations of each Stokes parameter of the light to be measured at the wafer are obtained.

[0158] When the maximum additional phase difference caused by the defocusing of the coupling mirror and the processing and alignment of the waveplate itself of the zero-order quarter-waveplate varies within the range of , the influencing degrees on each Stokes parameter at the wafer are different. Among them, the absolute detection errors of s0 and s1 are within ten percent, the absolute detection error of s2 is within five percent, and the absolute detection error of s3 is within five per thousand. This is related to the relatively small component of s3 in the incident light in the assumption. From this analysis, it can be seen that the waveplate error restricts the detection error of the light polarization state to be measured at the wafer to a great extent.

[0159] Next, the error analysis system for detecting the light polarization state at the wafer in the lithography machine provided by the present invention will be described. The error analysis system for detecting the light polarization state at the wafer in the lithography machine described below can be correspondingly referred to the error analysis method for detecting the light polarization state at the wafer in the lithography machine described above.

[0160] Please refer to Figure 18 , Figure 18 which is the structural schematic diagram of the error analysis system for detecting the light polarization state at the wafer in the lithography machine provided by the present invention.

[0161] The present invention also provides an error analysis system for detecting the optical polarization state at the wafer in a lithography machine, which is applied to the optical polarization state detection system at the wafer in the lithography machine. The detection system successively includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back. After the light beam at the wafer of the lithography machine becomes parallel light through the coupling mirror, it successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device. The error analysis system includes: an incident angle determination module 1801 for determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; an alignment calculation module 1802 for calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; a parameter determination module 1803 for determining the Stokes parameters of the light at the wafer in the non-ideal element state according to the wave plate phase delay, where the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism are considered in the non-ideal element state; and an analysis result determination module 1804 for determining the error analysis result of the optical polarization state detection at the wafer according to the Stokes parameters of the light at the wafer in the non-ideal element state and the Stokes parameters of the light at the wafer in the preset ideal element state.

[0162] The optical polarization state detection system at the wafer in the lithography machine provided by the present invention will be described below. The optical polarization state detection system at the wafer in the lithography machine described below can be correspondingly referred to the error analysis method for detecting the optical polarization state at the wafer in the lithography machine described above.

[0163] The present invention also provides an optical polarization state detection system at the wafer in a lithography machine, characterized in that the error analysis method for detecting the optical polarization state at the wafer in the lithography machine described above is used for error analysis.

[0164] The lithography machine provided by the present invention will be described below. The lithography machine described below can be correspondingly referred to the error analysis method for detecting the optical polarization state at the wafer in the lithography machine described above.

[0165] The present invention also provides a lithography machine, characterized in that it includes the optical polarization state detection system at the wafer in the lithography machine described above.

[0166] Figure 19 The structural schematic diagram of an electronic device is illustrated, such as Figure 19As shown in the figure, the electronic device may include: a processor 1901, a communications interface 1902, a memory 1903, and a communication bus 1904. Among them, the processor 1901, the communications interface 1902, and the memory 1903 complete mutual communication through the communication bus 1904. The processor 1901 may call the logical instructions in the memory 1903 to execute the error analysis method for detecting the light polarization state at the silicon wafer in the lithography machine, which is applied to the light polarization state detection system at the silicon wafer in the lithography machine. The detection system successively includes a coupling mirror, a zero-order 1 / 4 wave plate, a polarization prism, and a charge-coupled device from front to back; the light beam at the silicon wafer of the lithography machine becomes parallel light after passing through the coupling mirror, and then successively passes through the zero-order 1 / 4 wave plate and the polarization prism and is received by the charge-coupled device; the method includes: determining the incident angle of the light beam incident on the zero-order 1 / 4 wave plate according to the defocus amount of the coupling mirror; calculating the wave plate phase delay corresponding to the alignment error of the zero-order 1 / 4 wave plate according to the incident angle of the light beam of the zero-order 1 / 4 wave plate; determining the Stokes parameters of the light at the silicon wafer in the non-ideal element state according to the wave plate phase delay; considering the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism in the non-ideal element state; determining the error analysis result of the light polarization state detection at the silicon wafer according to the Stokes parameters of the light at the silicon wafer in the non-ideal element state and the Stokes parameters of the light at the silicon wafer in the preset ideal element state.

[0167] In addition, when the logical instructions in the above-mentioned memory 1903 can be implemented in the form of software functional units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The foregoing storage medium includes: various media such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk, or an optical disc that can store program codes.

[0168] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the error analysis method for detecting the optical polarization state at the wafer in the lithography machine provided by the above-mentioned various methods, which is applied to the optical polarization state detection system at the wafer in the lithography machine. The detection system successively includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back; the beam at the wafer of the lithography machine becomes parallel light after passing through the coupling mirror, and then successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device; the method includes: determining the incident angle of the beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the beam on the zero-order quarter-wave plate; determining the Stokes parameters of the light at the wafer in the non-ideal element state according to the wave plate phase delay; considering the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism in the non-ideal element state; determining the error analysis result of the optical polarization state detection at the wafer according to the Stokes parameters of the light at the wafer in the non-ideal element state and the Stokes parameters of the light at the wafer in the preset ideal element state.

[0169] On another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it realizes the error analysis method for detecting the optical polarization state at the wafer in the lithography machine provided by the above-mentioned various methods, which is applied to the optical polarization state detection system at the wafer in the lithography machine. The detection system successively includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back; the beam at the wafer of the lithography machine becomes parallel light after passing through the coupling mirror, and then successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device; the method includes: determining the incident angle of the beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the beam on the zero-order quarter-wave plate; determining the Stokes parameters of the light at the wafer in the non-ideal element state according to the wave plate phase delay; considering the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism in the non-ideal element state; determining the error analysis result of the optical polarization state detection at the wafer according to the Stokes parameters of the light at the wafer in the non-ideal element state and the Stokes parameters of the light at the wafer in the preset ideal element state.

[0170] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0171] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An error analysis method for detecting the light polarization state at the silicon wafer in a lithography machine, characterized in that A light polarization state detection system applied to a silicon wafer in a lithography machine. The detection system successively includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back. After the light beam at the silicon wafer of the lithography machine is turned into parallel light by the coupling mirror, it successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device; The method includes: Determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; Calculating the wave plate phase delay corresponding to the processing error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; Calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; Determining the Stokes parameters of the light at the silicon wafer in the non-ideal element state according to the wave plate phase delay; the non-ideal element state considers the wave plate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism; the wave plate phase delay of the zero-order quarter-wave plate is the phase delay caused by the defocus of the coupling mirror, the processing and alignment of the wave plate itself; Determining the error analysis result of the light polarization state detection at the silicon wafer according to the Stokes parameters of the light at the silicon wafer in the non-ideal element state and the Stokes parameters of the light at the silicon wafer in the preset ideal element state.

2. The error analysis method for detecting the optical polarization state at the silicon wafer in the lithography machine according to claim 1, wherein The determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror includes: Determining the object-side coordinates after defocus of the coupling mirror according to the defocus amount of the coupling mirror and the focal length of the coupling mirror; Determining the image point position after defocus of the coupling mirror according to the object-side coordinates and the defocus amount; Determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the clear aperture of the coupling mirror and the image point position.

3. The error analysis method for detecting the light polarization state at the silicon wafer in the lithography machine according to claim 1, wherein When the defocus amount of the coupling mirror is within the range of ±100 nm, the light beam incident on the zero-order quarter-wave plate is a conical light beam.

4. The error analysis method for detecting the light polarization state at the silicon wafer in the lithography machine according to claim 1, characterized in that, Before calculating the wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate, it further includes: Selecting the structural parameters of the zero-order quarter-wave plate; the structural parameters include the thickness of the first structural crystal and the thickness of the second structural crystal; Calculating the initial phase delay of the zero-order quarter-wave plate according to the structural parameters to calculate the wave plate phase delay corresponding to the alignment error based on the initial phase delay.

5. The error analysis method for detecting the light polarization state at the silicon wafer in the lithography machine according to claim 1, characterized in that, The wave plate phase delay corresponding to the alignment error of the zero-order quarter-wave plate is greater than the wave plate phase delay corresponding to the processing error of the zero-order quarter-wave plate.

6. The error analysis method for detecting the light polarization state at the silicon wafer in the lithography machine according to claim 1, characterized in that When the wave plate phase delay caused by the defocusing of the coupling mirror, the processing and alignment of the wave plate itself for the zero-order 1 / 4 wave plate is within the absolute detection errors of the Stokes parameters s0 and s1 of the light at the silicon wafer are within ten percent, the absolute detection error of s2 is within five percent, and the absolute detection error of s3 is within five per thousand.

7. An error analysis system for detecting the light polarization state at the silicon wafer in a lithography machine, characterized in that, A light polarization state detection system applied to a silicon wafer in a lithography machine. The detection system successively includes a coupling mirror, a zero-order quarter-wave plate, a polarization prism, and a charge-coupled device from front to back. After the light beam at the silicon wafer of the lithography machine is turned into parallel light by the coupling mirror, it successively passes through the zero-order quarter-wave plate and the polarization prism and is received by the charge-coupled device; The error analysis system includes: An incident angle determination module for determining the incident angle of the light beam incident on the zero-order quarter-wave plate according to the defocus amount of the coupling mirror; A calculation module, configured to calculate the waveplate phase delay corresponding to the processing error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; calculate the waveplate phase delay corresponding to the alignment error of the zero-order quarter-wave plate according to the incident angle of the light beam of the zero-order quarter-wave plate; A parameter determination module, configured to determine the Stokes parameters of the light at the silicon wafer in the non-ideal element state according to the waveplate phase delay; the non-ideal element state takes into account the waveplate phase delay of the zero-order quarter-wave plate and the bidirectional attenuation rate of the polarization prism; the waveplate phase delay of the zero-order quarter-wave plate is the phase delay caused by the defocusing of the coupling mirror, the processing and alignment of the waveplate itself; An analysis result determination module, configured to determine the error analysis result of the polarization state detection of the light at the silicon wafer according to the Stokes parameters of the light at the silicon wafer in the non-ideal element state and the Stokes parameters of the light at the silicon wafer in the preset ideal element state.

8. A light polarization state detection system at the silicon wafer in a lithography machine, characterized in that, Perform error analysis by using the error analysis method for the polarization state detection of the light at the silicon wafer in the lithography machine according to any one of claims 1 to 6.

9. A lithography machine, characterized in that, Include the polarization state detection system of the light at the silicon wafer in the lithography machine according to claim 8.

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