Error analysis method for light polarization state detection at silicon wafer in photoetching machine

Abstract

The invention relates to the technical field of polarization detection, and provides an error analysis method for light polarization state detection at a silicon wafer in a photoetching machine, and the method comprises the steps: determining an incident angle of a light beam entering a zero-order 1 / 4 wave plate according to the defocusing amount of a coupling mirror; calculating wave plate phase delay corresponding to the adjustment 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 a Stokes parameter of light at the silicon wafer in a non-ideal element state according to the wave plate phase delay; the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism are considered in the non-ideal element state; and according to the Stokes parameter of the light at the silicon wafer in the non-ideal element state and the Stokes parameter of the light at the silicon wafer in a preset ideal element state, determining an error analysis result of light polarization state detection at the silicon wafer. According to the invention, accurate error analysis of light polarization state detection at the silicon wafer can be realized, photoetching simulation is facilitated, the design of a photoetching machine system is optimized, and finally the photoetching imaging quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of polarization detection technology, and in particular to an error analysis method for detecting the polarization state of light at a silicon wafer in a photolithography machine. Background Technology

[0002] With the continuous increase of the numerical aperture (NA) of the lithography system and the decreasing critical dimension (CD) of the exposed pattern feature, the polarization characteristics of light have an increasingly significant impact on the lithography performance. The detection error of the polarization state detection system at the lithography machine silicon wafer is a key indicator for measuring the detection quality. Therefore, accurate measurement and in-depth analysis of the detection system can not only provide an important basis for lithography simulation, but also optimize the lithography machine system design, thereby significantly improving the lithography imaging quality. SUMMARY OF THE INVENTION

[0003] The present invention provides an error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine, which can realize accurate error analysis of the polarization state of light at a silicon wafer, is helpful for lithography simulation, optimizes the lithography machine system design, and ultimately improves the lithography imaging quality.

[0004] The present invention provides an error analysis method for detecting the polarization state of light at a silicon wafer in a photolithography machine, which is applied to a detection system for the polarization state of light at a silicon wafer in a photolithography machine. The detection system comprises, from front to back, a coupling mirror, a zero-order 1 / 4 wave plate, a polarization prism and a charge-coupled device; after the light beam at the silicon wafer of the photolithography machine is converted into parallel light by the coupling mirror, it passes through the zero-order 1 / 4 wave plate and the polarization prism successively and is received by the charge-coupled device; the method comprises: 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; According to the incident angle of the light beam of the zero-order 1 / 4 wave plate, the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate is calculated; the Stokes parameter of the light at the silicon wafer in the non-ideal component state is determined according to the wave plate phase delay; the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism are considered in the non-ideal component state; according to the Stokes parameter of the light at the silicon wafer in the non-ideal component state and the Stokes parameter of the light at the silicon wafer in the preset ideal component state, the error analysis result of the polarization state detection of the light at the silicon wafer is determined.

[0005] According to an error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine provided by the present invention, the incident angle of the light beam incident on the zero-order 1 / 4 wave plate is determined according to the defocus amount of the coupling mirror, including: determining the object coordinates of the coupling mirror after defocusing according to the defocus amount of the coupling mirror and the focal length of the coupling mirror; determining the image point position of the coupling mirror after defocusing according to the object coordinates and the defocus amount; determining the incident angle of the light beam incident on the zero-order 1 / 4 wave plate according to the clear aperture of the coupling mirror and the image point position.

[0006] According to the error analysis method for detecting the polarization state of light at a silicon wafer in a photolithography machine provided by the present invention, the defocus of the coupling mirror is within the range of ±100nm, and the light beam incident on the zero-order 1 / 4 wave plate is a conical light beam.

[0007] According to an error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine provided by the present invention, before calculating the wave plate phase delay corresponding to the adjustment 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, the method further includes: selecting structural parameters of the zero-order 1 / 4 wave plate; the structural parameters include the thickness of the first structure crystal and the thickness of the second structure crystal; calculating the initial phase delay of the zero-order 1 / 4 wave plate according to the structural parameters, so as to calculate the wave plate phase delay corresponding to the adjustment error based on the initial phase delay.

[0008] According to the error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine provided by the present invention, after 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, it also includes: calculating the wave plate phase delay corresponding to the processing 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.

[0009] According to an error analysis method for detecting polarization state of light at a silicon wafer in a lithography machine provided by the present invention, the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate is greater than the wave plate phase delay corresponding to the processing error of the zero-order 1 / 4 wave plate.

[0010] According to an error analysis method for detecting polarization state of light at a silicon wafer in a photolithography machine provided by the present invention, when the zero-order 1 / 4 wave plate is defocused by the coupling mirror, and the wave plate itself is processed and adjusted, the wave plate phase delay is In the range of , the Stokes parameter s of the light at the silicon wafer 0 and s 1 The absolute detection error of is 10%, s 2 The absolute detection error is 5%, s 3 The absolute detection error of is 0.5%.

[0011] ​The present invention also provides an error analysis system for detecting the polarization state of light at a silicon wafer in a photolithography machine, which is applied to the detection system for the polarization state of light at a silicon wafer in a photolithography machine. The detection system comprises, from front to back, a coupling mirror, a zero-order 1 / 4 wave plate, a polarization prism and a charge-coupled device; after the light beam at the silicon wafer of the photolithography machine is converted into parallel light by the coupling mirror, it passes through the zero-order 1 / 4 wave plate and the polarization prism successively and is received by the charge-coupled device; the error analysis system comprises: an incident angle determination module, which is used to determine the incident angle of the light beam incident to the zero-order 1 / 4 wave plate according to the defocus amount of the coupling mirror; an adjustment calculation module, which is used to calculate the incident angle of the light beam incident to the zero-order 1 / 4 wave plate according to the defocus amount of the coupling mirror; and an adjustment calculation module, which is used to calculate the incident angle of the light beam incident to the zero-order 1 / 4 wave plate according to the defocus amount of the coupling mirror. According to the incident angle of the light beam of the zero-order 1 / 4 wave plate, the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate is calculated; the parameter determination module is used to determine the Stokes parameter of the light at the silicon wafer in the non-ideal component state according to the wave plate phase delay; the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism are considered in the non-ideal component state; the analysis result determination module is used to determine the error analysis result of the polarization state detection of the light at the silicon wafer according to the Stokes parameter of the light at the silicon wafer in the non-ideal component state and the Stokes parameter of the light at the silicon wafer in the preset ideal component state.

[0012] The present invention also provides a light polarization state detection system at a silicon wafer in a lithography machine, characterized in that the error analysis method for detecting light polarization state at a silicon wafer in a lithography machine is used to perform error analysis.

[0013] The present invention also provides a photolithography machine, characterized by comprising the above-mentioned photolithography machine at the silicon wafer light polarization state detection system.

[0014] The present invention provides an error analysis method for detecting the polarization state of light at a silicon wafer in a photolithography machine. The method comprises the following steps: determining the incident angle of a light beam incident on a zero-order 1 / 4 wave plate according to the defocus amount of a coupling mirror; calculating the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate according to the incident angle of the light beam at the zero-order 1 / 4 wave plate; determining the Stokes parameter of the light at the silicon wafer in a non-ideal component 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 component state; and determining the error analysis result of the polarization state detection of light at the silicon wafer according to the Stokes parameter of the light at the silicon wafer in a non-ideal component state and the Stokes parameter of the light at the silicon wafer in a preset ideal component state. The present invention can realize accurate error analysis of the polarization state detection of light at the silicon wafer, which is helpful for photolithography simulation, optimizing the photolithography machine system design, and ultimately improving the photolithography imaging quality. Brief Description of the Figures

[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 This is a flow chart of the error analysis method for detecting the polarization state of light at a silicon wafer in a photolithography machine provided by the present invention.

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

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

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

[0020] Figure 5 The present invention provides that when the thickness of the first structure crystal and the second structure crystal in the zero-order 1 / 4 wave plate are respectively When the processing error is greater than 0.01, the additional phase delay caused by the thickness processing error is shown in the figure.

[0021] Figure 6 The present invention provides that when the optical axis of the first structure crystal in the zero-order 1 / 4 wave plate has When the processing error is greater than 0.01, the additional phase delay caused by the optical axis processing error is shown in the figure.

[0022] Figure 7 The present invention provides that when the optical axis of the second structure crystal in the zero-order 1 / 4 wave plate has When the processing error is greater than 0.01, the additional phase delay caused by the optical axis processing error is shown in the figure.

[0023] Figure 8 This is a schematic diagram of the zero-order 1 / 4 wave plate provided by the present invention rotating around the x-axis.

[0024] Figure 9 is the angle of incidence provided by the present invention Take 、 、 and , the additional phase delay varies with the incident angle and the rotation angle around the x-axis 's changing trend chart (a sub-chart is , subgraph b is , subgraph c is , d subgraph is ).

[0025] Figure 10 is the incident angle provided by the present invention at changes, the azimuth of the incident surface also changes When taking values, the additional delay varies with the rotation angle around the x-axis.

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

[0027] Figure 12 is the angle of incidence provided by the present invention Take 、 、 and , the additional phase delay varies with the incident angle and the rotation angle around the y-axis 's changing trend chart (a sub-chart is , subgraph b is , subgraph c is , d subgraph is ).

[0028] Figure 13 is the incident angle provided by the present invention at changes, the azimuth of the incident surface also changes When taking values, the additional delay varies with the rotation angle around the y-axis.

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

[0030] Figure 15 is the angle of incidence provided by the present invention Take 、 、 and , the additional phase delay varies with the incident angle and the rotation angle around the z-axis 's changing trend chart (a sub-chart is , subgraph b is , subgraph c is , d subgraph is ).

[0031] Figure 16 is the incident angle provided by the present invention at changes, the azimuth of the incident surface also changes When taking values, the additional delay varies with the rotation angle around the z-axis.

[0032] Figure 17 The invention provides that when there is a zero-order 1 / 4 wave plate When the additional phase difference is 0.04, the error diagram of each Stokes parameter caused by it.

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

[0034] Figure 19 This is a schematic diagram of the structure of the electronic device provided by the present invention. Specific implementation method

[0035] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection 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 large polarization effects, which seriously affect the image quality. Therefore, it is particularly important to accurately measure and control the polarization characteristics of ultra-high NA imaging systems. Detection error is one of the important indicators of measurement quality. The detection accuracy of the polarization meter is affected by the errors of each detection element inside it. The light polarization state detection instrument at the silicon wafer is mainly composed of a coupling mirror, a zero-order 1 / 4 wave plate, a polarizing prism and a CCD (Charge-Coupled Device). However, due to various errors that may occur in the detection process of the coupling mirror and wave plate due to processing and adjustment, there is currently no error analysis method for this type of detection technology.

[0037] Please refer to Figure 1 , Figure 1 This is a flow chart of the error analysis method for detecting the polarization state of light at a 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 of measuring the polarization state of light on a silicon wafer provided by the present invention.

[0039] The present invention provides an error analysis method for detecting the polarization state of light at a silicon wafer in a photolithography machine, which is applied to a detection system for the polarization state of light at a silicon wafer in a photolithography machine. The detection system comprises a coupling mirror, a zero-order 1 / 4 wave plate, a polarization prism and a charge-coupled device in sequence from front to back; the light beam at the silicon wafer of the photolithography machine is converted into parallel light by 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: 101: Determine the incident angle of the light beam incident on the zero-order 1 / 4 wave plate according to the defocusing amount of the coupling mirror; 102: According to the incident angle of the light beam of the zero-order 1 / 4 wave plate, calculate the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate; 103: Determine the Stokes parameters of light at the silicon wafer under non-ideal component conditions based on the wave plate phase delay; consider the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism under non-ideal component conditions; 104: According to the Stokes parameters of the light at the silicon wafer under the non-ideal component state and the Stokes parameters of the light at the silicon wafer under the preset ideal component state, the error analysis result of the polarization state detection of the light at the silicon wafer is determined.

[0040] In order to analyze the influence of each component error on the detection result, the present invention derives the expression of the Stokes parameter of the light at the silicon chip, which contains both the delay characteristics of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate characteristics of the polarization prism (non-ideal component state), which provides a theoretical basis for data processing, error analysis and system calibration in future experiments. And the influence of the coupling mirror defocus and the delay error of the zero-order 1 / 4 wave plate on the detection error of the polarization state of the light at the silicon chip is specifically analyzed.

[0041] The detection principle of the detector of the polarization state of light at the silicon wafer of the lithography machine is: after the high NA light beam at the silicon wafer of the lithography machine is converted into parallel light by the coupling mirror, it passes through the zero-order 1 / 4 wave plate and the polarization prism successively and is received by the CCD. During the measurement, the zero-order 1 / 4 wave plate is rotated with the optical axis of the lithography machine system as the axis. Assuming that there are N modulation points in one rotation of the wave plate, the CCD collects an image once for each modulation point. Draw a two-dimensional curve graph based on 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, the Stokes parameter of each point on the pupil is calculated through the relationship between the Fourier coefficient and the Stokes parameter.

[0042] ​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 successively passes through a rotatable zero-order quarter-wave plate and a polarization prism with a fixed azimuth angle 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, and the image sensor collects an image each time the wave plate rotates. 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: fixing the azimuth angle of the polarization prism effectively avoids the influence of the polarization selectivity of the photosensitive surface of the photodetector on the detection; there are more sampling points during the measurement, so compared with a polarization measuring instrument with only a limited number of wave plate-polarizer combinations, 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 Is then converted into : , 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 components, that is, the retardance of the zero-order quarter-wave plate And the bidirectional attenuation rate of the polarization prism When, the Stokes parameters of the light at the wafer under the preset ideal component state are: , 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.

[0043] For the need of high detection accuracy and error analysis in a high-NA lithography system, the present invention deduces the solution process of the polarization state of the light at the wafer in the lithography system in the non-ideal component state after considering the system errors (characteristic parameters of the coupling mirror, zero-order quarter-wave plate, and polarization prism).

[0044] First, deduce the solution process of the polarization state of the light at the wafer of the lithography machine when 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: , , Among them, is the azimuth angle of the polarizing prism, is the azimuth of the zero-order 1 / 4 wave plate, is the bidirectional attenuation rate through the polarizing prism, is the phase delay of the zero-order 1 / 4 wave plate.

[0045] If , Among them First column elements: , Second column elements: , The third column element: , The fourth column element: .

[0046] The measurement process is to rotate the zero-order 1 / 4 wave plate with the optical axis of the entire optical system as the axis, and then the transmitted light intensity I The corresponding relationship with the Stokes parameter at the silicon wafer is: , Among them, ; is the angular velocity of the wave plate. Assume that the wave plate rotates once with modulation points, then the rotation step angle of the wave plate , . Transmitted light intensity I It can be expanded into Fourier series form: , , Among them, is the light intensity value measured at each modulation point, and , The Stokes parameter at the silicon wafer is used as a variable and the least square method is used to determine it. From this, the Stokes parameter can be obtained as follows: , From the above formula, we can see that in the actual measurement process, we first obtain the light intensity curve through the corresponding relationship between each angle of the zero-order 1 / 4 wave plate rotation and the light intensity value. Then, by performing Fourier analysis on the curve, we can find the Stokes parameters of the light to be measured at the silicon wafer.

[0047] The present invention analyzes the change in the incident angle of the subsequent detection optical path when the coupling mirror in the polarization state detection device is defocused. Then, the additional phase difference caused by the adjustment of the zero-order wave plate is used to specifically analyze the phase delay change of the zero-order 1 / 4 wave plate when the zero-order 1 / 4 wave plate rotates or tilts around a certain coordinate axis when detecting the various Stokes parameters of the light to be measured at the silicon wafer in the lithography system. The wave plate error largely restricts the detection error of the polarization state of the light to be measured at the silicon wafer. The present invention can realize accurate error analysis of the detection of the polarization state of light at the silicon wafer, which is helpful for lithography simulation, optimizes the design of the lithography machine system, and ultimately improves the lithography imaging quality.

[0048] As a preferred embodiment, the incident angle of the light beam incident on the zero-order 1 / 4 wave plate is determined according to the defocus amount of the coupling mirror, including: determining the object coordinates of the coupling mirror after defocusing according to the defocus amount of the coupling mirror and the focal length of the coupling mirror; determining the image point position after defocusing the coupling mirror according to the object coordinates and the defocus amount; determining the incident angle of the light beam incident on the zero-order 1 / 4 wave plate according to the clear aperture of the coupling mirror and the image point position.

[0049] As a preferred embodiment, the defocus of the coupling mirror is within the range of ±100nm, and the light beam incident on the zero-order 1 / 4 wave plate is a conical light beam.

[0050] Please refer to Figure 3 , Figure 3 This is a diagram showing the change in incident angle of the subsequent optical path caused by the defocusing of the coupling mirror provided by the present invention.

[0051] Please refer to Figure 4 , Figure 4 This is a diagram showing the corresponding relationship between the defocusing amount of the coupling mirror provided by the present invention and the incident angle of the wave plate.

[0052] Compared with the mask surface, the incident angle range of the light to be measured at the silicon wafer is several times that of the mask surface, except that the azimuth angle of the incident surface is the same. The polarization elements used in this embodiment include two zero-order 1 / 4 wave plates and a polarization prism. However, a coupling mirror needs to be added before these two polarization elements to convert the large-angle incident light beam into parallel light. After the coupling mirror is introduced, it is necessary to analyze the impact it has on polarization detection, such as: the defocus of the coupling mirror will cause the change of the incident angle of the subsequent light path.

[0053] The focal length of the coupling mirror is , the object point position and image point position are and , the defocus of the coupling mirror . According to Gauss's formula , Relationship between the object focal length and image focal length of an optical system in air , You can get: .

[0054] After the coupling mirror is defocused, its object coordinates are: , After the coupling mirror is defocused, the image point position is: .

[0055] If the aperture of the coupling mirror is , after the coupling mirror is defocused, the incident angle formed on the surface of the subsequent polarization detection element is no longer zero, but .

[0056] Through the above derivation, we know that when the coupling mirror has a known aperture , focal length and defocus amount After that, the effect of the coupling mirror defocus on the parallelism of its outgoing beam can be calculated.

[0057] For a projection objective with NA=1.35, when =6.8mm, =-5348mm, and In When the wavelength changes within the range of 100nm, the angle between the light beam incident on the zero-order 1 / 4 wave plate surface and the normal of the wave plate surface (i.e. the incident angle of the light beam) can be obtained. ) and The corresponding relationship.

[0058] Defocusing the coupling mirror Within the range of 100nm, the light beam emitted from it is no longer a normal incident light parallel to the optical axis of the system, but a conical light beam with a certain incident angle (i.e. , ).

[0059] The defocus of the coupling mirror will cause the 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 1 / 4 wave plate, and then affect the detection accuracy of the polarization state. Through the above steps, the effect of the coupling mirror defocus on the incident angle can be accurately calculated, providing a theoretical basis for subsequent error analysis and system optimization.

[0060] ​​​As a preferred embodiment, before calculating the wave plate phase delay corresponding to the adjustment 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, the method further includes: selecting the structural parameters of the zero-order 1 / 4 wave plate; the structural parameters include the thickness of the first structure crystal and the thickness of the second structure crystal; calculating the initial phase delay of the zero-order 1 / 4 wave plate according to the structural parameters, so as to calculate the wave plate phase delay corresponding to the adjustment error based on the initial phase delay.

[0061] Please refer to Figure 5 , Figure 5 The thickness of the first structure crystal and the second structure crystal in the zero-order 1 / 4 wave plate provided by the present invention are respectively When the processing error is greater than 0.01, the additional phase delay caused by the thickness processing error is shown in the figure.

[0062] Please refer to Figure 6 , Figure 6 When the optical axis of the first structure crystal in the zero-order 1 / 4 wave plate provided by the present invention has When the processing error is greater than 0.01, the additional phase delay caused by the optical axis processing error is shown in the figure.

[0063] Please refer to Figure 7 , Figure 7 When the optical axis of the second structure crystal in the zero-order 1 / 4 wave plate provided by the present invention has When the processing error is greater than 0.01, the additional phase delay caused by the optical axis processing error is shown in the figure.

[0064] The zero-order 1 / 4 wave plate is an important component of the optical polarization state detection instrument at the silicon wafer. In this embodiment, the structural parameters of the zero-order 1 / 4 wave plate are specifically designed.

[0065] The zero-order 1 / 4 wave plate is made of positive crystal, and it is usually composed of two multi-order 1 / 4 wave plates with almost the same characteristics. When the incident light meets When the conditions are met, the delay of the multi-stage 1 / 4 wave plate is: , Among them, and is the principal refractive index of the positive crystal, is the thickness of the multi-stage 1 / 4 wave plate, is a positive integer, is the wavelength of the incident light.

[0066] .

[0067] In the actual application of the polarization state detection of the beam at the silicon wafer in the immersion lithography machine, the zero-order 1 / 4 wave plate is made of positive crystal fluorite (MgF 2 ) is made in =193nm, its principal refractive index is =1.441 and =1.428. When the thickness of the 1 / 4 wave plate of fluorite is about Select =13. Then the initial thickness of the first fluorite wave plate (first structure crystal) is .

[0068] Adjust the thickness of the two fluorite crystals so that the thickness difference between the two pieces is equal to the thickness of the single-piece zero-order 1 / 4 wave plate, that is, . Therefore, the initial thickness of the second fluorite wave plate (second structure crystal) is .

[0069] The initial thickness of the zero-order 1 / 4 wave plate is thus obtained Then calculate the initial phase delay of the zero-order 1 / 4 wave plate: .

[0070] Wherein, the angle of incidence , azimuth of the incident surface . Corresponding to the initial thickness Delay amount The initial value of is .

[0071] Then Substitute the initial value of into the objective function , get the initial phase delay and the ideal phase delay of the zero-order 1 / 4 wave plate Differences .

[0072] Assume that the possible range of thickness parameters of the two crystals in the zero-order quarter-wave plate is set to .

[0073] Afterwards you will get N Group Thickness Parameters . During the calculation process, use The step size of and .

[0074] Global Optimal Thickness of Two Crystals . The amount of change in latency difference is effectively reduced to , and The initial value of is significantly higher than this value.

[0075] ​​​​As a preferred embodiment, after 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, the method further includes: calculating the wave plate phase delay corresponding to the processing error of the zero-order 1 / 4 wave plate according to the incident angle of the light beam incident on the zero-order 1 / 4 wave plate.

[0076] The zero-order 1 / 4 wave plate is an important component in the instrument for detecting the polarization state of light on a silicon wafer. The quality of its performance directly affects the detection accuracy of the Stokes parameters of light on a silicon wafer. However, various errors may occur in the detection process due to processing or adjustment of this wave plate. When detecting the polarization state of light on a silicon wafer, two zero-order wave plates made of the same material are used. It is necessary to analyze the additional phase difference caused by processing errors such as the thickness of each crystal inside the zero-order wave plate and the direction of the optical axis.

[0077] In this embodiment, the thickness of each zero-order quarter wave plate varies , the phase delay is transformed into: , When the thickness of the two plates in the zero-order 1 / 4 wave plate is and Respective changes , the additional delay can basically be varied within Within.

[0078] The optical axis of each zero-order wave plate changes due to processing misalignment , the phase delay is transformed into: , When the optical axis directions of the two plates in the zero-order 1 / 4 wave plate change respectively , the additional delay range is .

[0079] As a preferred embodiment, the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate is greater than the wave plate phase delay corresponding to the processing error of the zero-order 1 / 4 wave plate.

[0080] In this embodiment, the influence of the additional phase difference of the zero-order 1 / 4 wave plate on its own adjustment error is specifically analyzed.

[0081] Please refer to Figure 8 , Figure 8 This is a schematic diagram of the zero-order 1 / 4 wave plate provided by the present invention rotating around the x-axis.

[0082] Please refer to Figure 9 , Figure 9 The azimuth angle of the incident surface provided by the present invention Take 、 、 and ​When the additional phase delay increases with the incident angle and the rotation angle around the x-axis 's changing trend chart (a sub-chart is , subgraph b is , subgraph c is , d subgraph is ).

[0083] Please refer to Figure 10 , Figure 10 The incident angle provided by the present invention is changes, the azimuth of the incident surface also changes When taking values, the additional delay varies with the rotation angle around the x-axis.

[0084] When the two-piece zero-order wave plate rotates around the x-axis, its phase delay is transformed into: , Among them, is the incident angle, is the azimuth of the incident surface, is the rotation angle of the zero-order 1 / 4 wave plate around the x-axis.

[0085] The zero-order 1 / 4 wave plate rotates around the x-axis , the additional phase delay caused is: .

[0086] When the light beam emitted from the coupling mirror is in contact with the wave plate interface , the wave plate rotates around the x-axis When and 's graphics about 's plane symmetry; and 's graphics about plane symmetry. When the incident plane azimuth or , the additional phase difference caused by the rotation of the wave plate around the x-axis is the largest. And when When these four azimuth angles change, the additional phase delay difference . Incident on the two-piece MgF 2 All incident light rays of the zero-order 1 / 4 wave plate, that is, the incident angle is changes, the azimuth of the incident surface also changes When taking the value, the additional phase delay value rotates around the x-axis with the zero-order 1 / 4 wave plate in the range of .

[0087] Please refer to Figure 11 , Figure 11 This is a schematic diagram of the zero-order 1 / 4 wave plate provided by the present invention rotating around the y-axis. ​

[0088] Please refer to Figure 12 , Figure 12 The azimuth angle of the incident surface provided by the present invention Take 、 、 and , the additional phase delay varies with the incident angle and the rotation angle around the y-axis 's changing trend chart (a sub-chart is , subgraph b is , subgraph c is , d subgraph is ).

[0089] Please refer to Figure 13 , Figure 13 The incident angle provided by the present invention is changes, the azimuth of the incident surface also changes When taking values, the additional delay varies with the rotation angle around the y-axis.

[0090] When the two-piece zero-order wave plate rotates around the y-axis, its phase delay is transformed into: , Among them, is the incident angle, is the azimuth of the incident surface, is the rotation angle of the zero-order 1 / 4 wave plate around the y-axis.

[0091] Then the two zero-order wave plates rotate around the y-axis , the additional phase delay caused is: .

[0092] When the incident plane azimuth , the additional phase difference caused by the rotation of the wave plate around the y-axis is the largest. and is exactly the same. And when When these four azimuth angles change, the additional phase delay difference . The azimuth of the incident surface is , the angle of incidence is When taking the value, the additional phase delay caused by the rotation of the two zero-order 1 / 4 wave plates around the y-axis varies with the rotation angle Changes. For the angle of incidence Conical beam within the range, two zero-order 1 / 4 wave plates rotate around the y-axis , its delay variable is in Varies within the range.

[0093] Please refer to Figure 14 , Figure 14 ​​Schematic diagram of the zero-order quarter wave plate provided by the present invention rotating around the z-axis.

[0094] Please refer to Figure 15 , Figure 15 The azimuth angle of the incident surface provided by the present invention Take 、 、 and , the additional phase delay varies with the incident angle and the rotation angle around the z-axis 's changing trend chart (a sub-chart is , subgraph b is , subgraph c is , d subgraph is ).

[0095] Please refer to Figure 16 , Figure 16 The incident angle provided by the present invention is changes, the azimuth of the incident surface also changes When taking values, the additional delay varies with the rotation angle around the z-axis.

[0096] When the two-piece zero-order wave plate rotates around the z-axis, its phase delay is transformed into: , Among them, is the incident angle, is the azimuth of the incident surface, is the rotation angle of the zero-order 1 / 4 wave plate around the z-axis.

[0097] The two zero-order wave plates rotate around the z-axis , the additional phase delay caused is: .

[0098] When the incident plane azimuth , the additional phase difference caused by the rotation of the wave plate around the z-axis is the largest. The graph changes are not affected by the incident angle. However, when When these four azimuth angles change, the additional phase delay difference . The azimuth of the incident surface is , the angle of incidence is When taking the value, the additional phase delay caused by the rotation of the two zero-order 1 / 4 wave plates around the z-axis varies with the rotation angle Changes. For the angle of incidence Conical beam within the range, two zero-order 1 / 4 wave plates rotate around the z-axis , its delay variable is in Varies within the range.

[0099] ​From the analysis of the adjustment error caused by the rotation of the two zero-order wave plates around the coordinate axes, it can be seen that: when the two zero-order wave plates rotate around the coordinate axes , the single direction adjustment error is .

[0100] As a preferred embodiment, when the zero-order 1 / 4 wave plate is defocused by the coupling mirror, the wave plate itself is processed and adjusted to cause the wave plate phase delay in In the range of , the Stokes parameter s of the light at the silicon wafer 0 and s 1 The absolute detection error of is 10%, s 2 The absolute detection error of is within 5%, s 3 The absolute detection error of is 0.5%.

[0101] Please refer to Figure 17 , Figure 17 When the zero-order 1 / 4 wave plate provided by the present invention has When the additional phase difference is 0.04, the error diagram of each Stokes parameter caused by it.

[0102] According to the above analysis, when the defocus of the coupling mirror changes within ±100nm, the light beam emitted from it is no longer a normal incident light parallel to the optical axis of the system, but a conical light beam with a certain incident angle (i.e. , ). When this conical beam is superimposed on the processing error of the zero-order wave plate, the additional phase difference caused is less than , they have little effect on the detection of the polarization state of light at the silicon wafer in the high NA lithography system. However, when the conical beam is superimposed on the adjustment error of the zero-order wave plate rotating around the coordinate axis, the additional phase difference caused is relatively large.

[0103] Specific analysis of the rotation or tilt of the zero-order 1 / 4 wave plate around a certain coordinate axis when detecting the Stokes parameters of the light to be measured at the silicon wafer in the laboratory lithography system of NA1.35 , the maximum phase delay changes of the zero-order 1 / 4 wave plate are , and ; and the thickness processing error of the single crystal in the zero-order 1 / 4 wave plate is , or due to the misalignment error of the single crystal optical axis processing is , the additional phase delay of the zero-order 1 / 4 wave plate is and . The analysis results show that when the adjustment angle error of the two-piece zero-order 1 / 4 wave plate and the processing error of the single crystal optical axis are both , the additional phase difference caused by the latter is more than twenty times smaller than that caused by the former. The maximum additional phase difference caused by various factors in the zero-order 1 / 4 wave plate is ​If the Stokes parameter of the light to be measured at the silicon wafer is assumed to be , . Then place the zero-order 1 / 4 wave plate at Substitute the additional phase difference that varies within the range into the Stokes parameter formula to obtain the deviation of each Stokes parameter of the light to be measured at the silicon wafer.

[0104] When the maximum additional phase difference of the zero-order 1 / 4 wave plate caused by the defocusing of the coupling mirror, the processing and adjustment of the wave plate itself is When the range changes, each Stokes parameter at the silicon wafer is affected to different degrees, among which s 0 and s 1 The absolute detection error of is 10%, s 2 The absolute detection error is 5%, s 3 The absolute detection error of is 0.5%, which is consistent with the assumption that the incident light s 3 is smaller. From this analysis, it can be seen that the wave plate error largely restricts the detection error of the polarization state of the light to be measured at the silicon wafer.

[0105] The following is a description of the error analysis system for detecting the polarization state of light at a silicon wafer in a lithography machine provided by the present invention. The error analysis system for detecting the polarization state of light at a silicon wafer in a lithography machine described below and the error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine described above can be referred to each other.

[0106] Please refer to Figure 18 , Figure 18 This is a schematic diagram of the structure of the error analysis system for detecting the polarization state of light at the silicon wafer in the lithography machine provided by the present invention.

[0107] The present invention also provides an error analysis system for detecting the polarization state of light at a silicon wafer in a photolithography machine, which is applied to the detection system for the polarization state of light at a silicon wafer in a photolithography machine. The detection system includes a coupling mirror, a zero-order 1 / 4 wave plate, a polarization prism and a charge-coupled device in sequence from front to back; the light beam at the silicon wafer of the photolithography machine is converted into parallel light by 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 error analysis system includes: an incident angle determination module 1801, which is used to determine 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; an adjustment calculation module 1802, which is used to determine 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; The incident angle of the light beam of the zero-order 1 / 4 wave plate is used to calculate the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate; the parameter determination module 1803 is used to determine the Stokes parameter of the light at the silicon wafer under the non-ideal component state according to the wave plate phase delay; the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism are considered under the non-ideal component state; the analysis result determination module 1804 is used to determine the error analysis result of the polarization state detection of the light at the silicon wafer according to the Stokes parameter of the light at the silicon wafer under the non-ideal component state and the Stokes parameter of the light at the silicon wafer under the preset ideal component state.

[0108] The following is a description of the light polarization state detection system at the silicon wafer in the lithography machine provided by the present invention. The light polarization state detection system at the silicon wafer in the lithography machine described below and the error analysis method for detecting the light polarization state at the silicon wafer in the lithography machine described above can be referred to each other.

[0109] The present invention also provides a light polarization state detection system at a silicon wafer in a lithography machine, characterized in that the error analysis method for detecting light polarization state at a silicon wafer in a lithography machine is used to perform error analysis.

[0110] The following is a description of the lithography machine provided by the present invention. The lithography machine described below and the error analysis method for detecting the polarization state of light at the silicon wafer in the lithography machine described above can be referred to each other.

[0111] The present invention also provides a photolithography machine, characterized by comprising the above-mentioned photolithography machine at the silicon wafer light polarization state detection system.

[0112] Figure 19 An example of a structural diagram of an electronic device is shown below. Figure 19 ​As shown, the electronic device may include: a processor 1901, a communications interface 1902, a memory 1903 and a communication bus 1904, wherein the processor 1901, the communications interface 1902 and the memory 1903 communicate with each other through the communication bus 1904. The processor 1901 may call the logic instructions in the memory 1903 to execute the error analysis method for detecting the polarization state of light at the silicon wafer in the lithography machine, which is applied to the polarization state detection system of light at the silicon wafer in the lithography machine, and the detection system 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 is converted into parallel light by 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 light on the zero-order 1 / 4 wave plate according to the defocus amount of the coupling mirror. The incident angle of the light beam; according to the incident angle of the light beam of the zero-order 1 / 4 wave plate, calculate the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate; determine the Stokes parameter of the light at the silicon wafer under the non-ideal component state according to the wave plate phase delay; consider the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism under the non-ideal component state; determine the error analysis result of the polarization state detection of the light at the silicon wafer according to the Stokes parameter of the light at the silicon wafer under the non-ideal component state and the Stokes parameter of the light at the silicon wafer under the preset ideal component state.

[0113] In addition, the logic instructions in the above-mentioned memory 1903 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0114] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program 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 polarization state of light at a silicon wafer in a lithography machine provided by the above-mentioned methods, which is applied to a light polarization state detection system at a silicon wafer in a lithography machine. The detection system 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 is converted into parallel light by the coupling mirror, and then passes through the zero-order 1 / 4 wave plate and the polarization prism successively and then is transmitted by the charge-coupled device The method comprises: 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 adjustment 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 parameter of the light at the silicon wafer under the non-ideal component 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 under the non-ideal component state; determining the error analysis result of the polarization state detection of the light at the silicon wafer according to the Stokes parameter of the light at the silicon wafer under the non-ideal component state and the Stokes parameter of the light at the silicon wafer under the preset ideal component state.

[0115] On another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine provided by the above-mentioned methods, and is applied to a polarization state detection system for light at a silicon wafer in a lithography machine, wherein the detection system includes, from front to back, a coupling mirror, a zero-order 1 / 4 wave plate, a polarization prism, and a charge-coupled device; after the light beam at the silicon wafer of the lithography machine is converted into parallel light by the coupling mirror, it passes through the zero-order 1 / 4 wave plate and the polarization prism successively and is received by the charge-coupled device; the method includes: according to The defocus of the coupling mirror determines the incident angle of the light beam incident on the zero-order 1 / 4 wave plate; according to the incident angle of the light beam on the zero-order 1 / 4 wave plate, the wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate is calculated; the Stokes parameter of the light at the silicon wafer under the non-ideal component state is determined according to the wave plate phase delay; the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism are considered under the non-ideal component state; according to the Stokes parameter of the light at the silicon wafer under the non-ideal component state and the Stokes parameter of the light at the silicon wafer under the preset ideal component state, the error analysis result of the polarization state detection of the light at the silicon wafer is determined.

[0116] The device embodiments described above are merely illustrative, wherein 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, i.e., they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative effort.

[0117] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, or of course by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., and includes a number of instructions for 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.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for error analysis of light polarization state detection at a silicon wafer in a photolithography machine, characterized in that: The invention is applied to the light polarization state detection system at the silicon wafer in the photolithography machine, and the detection system comprises 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 photolithography machine is converted into parallel light by 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 comprises: 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 adjustment 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; Determine the Stokes parameter of the light at the silicon wafer in the non-ideal element state according to the wave plate phase delay; consider 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; According to the Stokes parameters of the light at the silicon wafer in the non-ideal component state and the Stokes parameters of the light at the silicon wafer in the preset ideal component state, an error analysis result of the polarization state detection of the light at the silicon wafer is determined.

2. The error analysis method for detecting polarization state of light at a silicon wafer in a lithography machine according to claim 1, characterized in that: 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 comprises: Determining the object coordinates of the coupling mirror after defocusing according to the defocus amount of the coupling mirror and the focal length of the coupling mirror; Determine the image point position of the coupling mirror after defocusing according to the object coordinates and the defocus amount; The incident angle of the light beam incident on the zero-order 1 / 4 wave plate is determined according to the light aperture of the coupling mirror and the image point position.

3. The error analysis method for detecting polarization state of light at a silicon wafer in a lithography machine according to claim 1, characterized in that: The defocusing amount of the coupling mirror is within the range of ±100 nm, and the light beam incident on the zero-order 1 / 4 wave plate is a conical light beam.

4. The error analysis method for detecting polarization state of light at a silicon wafer in a lithography machine according to claim 1, characterized in that: Before calculating the wave plate phase delay corresponding to the adjustment 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, the method further includes: Selecting structural parameters of the zero-order quarter wave plate; the structural parameters include the thickness of the first structure crystal and the thickness of the second structure crystal; The initial phase delay of the zero-order 1 / 4 wave plate is calculated according to the structural parameters, so as to calculate the wave plate phase delay corresponding to the adjustment error based on the initial phase delay.

5. The error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine according to any one of claims 1 to 4, characterized in that: After 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, the method further includes: According to the incident angle of the light beam of the zero-order 1 / 4 wave plate, the wave plate phase delay corresponding to the processing error of the zero-order 1 / 4 wave plate is calculated.

6. The error analysis method for detecting polarization state of light at a silicon wafer in a lithography machine according to claim 5, characterized in that: The wave plate phase delay corresponding to the adjustment error of the zero-order 1 / 4 wave plate is greater than the wave plate phase delay corresponding to the processing error of the zero-order 1 / 4 wave plate.

7. The error analysis method for detecting polarization state of light at a silicon wafer in a lithography machine according to claim 5, characterized in that: When the zero-order 1 / 4 wave plate is delayed by the coupling mirror defocusing, the wave plate processing and adjustment, When it is within the range, the absolute detection error of the Stokes parameters s0 and s1 of the light at the silicon wafer is 10%, the absolute detection error of s2 is 5%, and the absolute detection error of s3 is 0.5%.

8. An error analysis system for detecting polarization state of light at a silicon wafer in a photolithography machine, characterized in that: The invention is applied to the light polarization state detection system at the silicon wafer in the photolithography machine, and the detection system comprises 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 photolithography machine is converted into parallel light by 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 error analysis system comprises: An incident angle determination module, used to determine 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; An adjustment calculation module, used for calculating the wave plate phase delay corresponding to the adjustment 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; A parameter determination module, used to determine the Stokes parameter of the light at the silicon wafer in a non-ideal component state according to the wave plate phase delay; the wave plate phase delay of the zero-order 1 / 4 wave plate and the bidirectional attenuation rate of the polarization prism are considered in the non-ideal component state; The analysis result determination module is used to determine the error analysis result of the polarization state detection of the light at the silicon wafer according to the Stokes parameter of the light at the silicon wafer under the non-ideal component state and the Stokes parameter of the light at the silicon wafer under the preset ideal component state.

9. A light polarization state detection system at a silicon wafer in a photolithography machine, characterized in that: Error analysis is performed using the error analysis method for detecting the polarization state of light at a silicon wafer in a lithography machine as described in any one of claims 1 to 7.

10. A photolithography machine, characterized in that: It includes the light polarization state detection system at the silicon wafer in the lithography machine as described in claim 9.

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