A phase shift mask and a method for detecting the uniformity of slit light transmission of a photolithography machine

Abstract

The embodiment of the present application discloses a phase shift mask and a method for detecting slit light uniformity of a photolithography machine. The method comprises: using a first phase shift mask to expose a first test silicon wafer at different focal plane positions according to a preset exposure dose; detecting phase shift errors of each mark pattern at different focal plane positions, fitting a relationship curve between the phase shift errors and the focal plane positions, and obtaining a slope slope'; calculating a vertical intercept b' of a fitting straight line of the exposure dose corresponding to the slope slope of each mark pattern; and finally determining the uniformity of slit illumination according to the dispersion of the vertical intercept b' of each mark pattern. The embodiment of the present application can solve the problem that the existing illumination uniformity measurement can only be measured offline, not only can adapt to complex and variable actual working conditions, but also can quickly judge whether the vertical illumination system needs to be recalibrated, simplify the measurement process, ensure that the machine does not stop, and continue production.

Description

Technical Field

[0001] This invention relates to the field of lithography technology, and more particularly to a phase-shifting mask and a method for detecting the uniformity of light transmission through slits in a lithography machine. Background Technology

[0002] Currently, illumination uniformity testing of lithography machines primarily employs offline measurement strategies, utilizing sensors within the machine. However, these sensor measurements operate on a fixed pattern, failing to adapt to the complex and ever-changing actual operating conditions. Consequently, the final exposure results may differ from the sensor measurements. While process control units (CDUs) frequently used in the manufacturing process can characterize illumination uniformity to some extent, CDUs themselves are the result of multiple factors interacting, making it impossible to accurately measure illumination uniformity or pinpoint abnormal locations. Summary of the Invention

[0003] This invention provides a method for detecting the uniformity of light transmission in a phase-shifting mask and a slit in a lithography machine, enabling online uniformity detection, improving measurement accuracy, and ensuring continuous machine operation.

[0004] In a first aspect, embodiments of the present invention provide a phase-shifting mask for detecting the uniformity of light transmission in a lithography machine slit, the phase-shifting mask comprising a plurality of marker patterns arranged periodically along multiple rows and columns;

[0005] The marking pattern includes a plurality of periodically arranged and parallel light-shielding strips; the light-shielding strips include a first light-shielding strip and a second light-shielding strip, with at least one second light-shielding strip between two adjacent first light-shielding strips; a phase-shifting region is provided on one or both sides of the first light-shielding strip.

[0006] Optionally, the light passing through the phase-shift region undergoes a phase shift of π / 4 to π / 2.

[0007] Optionally, the length and width of the first light-shielding strip and the second light-shielding strip are equal.

[0008] Optionally, the first light-shielding strip and the second light-shielding strip are arranged alternately at equal intervals.

[0009] Optionally, the length of the first light-shielding strip is greater than 4 μm.

[0010] Optionally, the width of the phase-shifting region is equal to 1 / 8 to 1 / 2 of the distance between two adjacent light-shielding strips.

[0011] Optionally, the light-shielding strip further includes a third light-shielding strip, with at least two third light-shielding strips spaced between two adjacent first light-shielding strips, and at least one third light-shielding strip spaced between the first light-shielding strip and the second light-shielding strip;

[0012] The width of the third light-shielding strip is equal to the width of the first light-shielding strip, and the length of the third light-shielding strip is less than the length of the first light-shielding strip.

[0013] Secondly, embodiments of the present invention also provide a method for detecting the uniformity of light transmission in a lithography machine slit, using a phase-shifting mask as described in any one of the first aspects, the detection method comprising:

[0014] Provide the first phase-shifting mask and the first test silicon wafer;

[0015] Using the first phase-shift mask, multiple exposure areas on the first test silicon wafer are exposed at different focal plane positions according to a preset exposure dose. The first test silicon wafer includes a first preset number of exposure areas, and each exposure area includes an exposure pattern that corresponds one-to-one with a marker pattern in the first phase-shift mask and has a phase-shift error. The phase-shift error and focal plane position of the marker patterns in all exposure areas of the first test silicon wafer are linearly related, and the slope of the fitted line is slope. The slope of the same marker pattern is linearly related to the exposure dose within a preset interval, and the slope of the fitted line is α. The preset exposure dose is located within the preset interval of exposure doses.

[0016] The phase shift error of each marker pattern in each exposure area is detected, the relationship curve between the phase shift error of each marker pattern and the focal plane position is fitted, and the slope of the fitted line is obtained.

[0017] Based on the slope slope', the fitted linear relationship between the slope slope and the exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope slope and the exposure dose for each marked pattern, calculate the ordinate b' of the fitted linear relationship between the slope slope and the exposure dose Energy for each marked pattern.

[0018] The uniformity of slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer.

[0019] Optionally, before exposing multiple first test silicon wafers at different focal plane positions using the first phase-shifting mask according to a preset exposure dose, the method further includes:

[0020] Provide a second phase-shifting mask and a second test silicon wafer;

[0021] Using the second phase-shift mask, different exposure areas on the second test silicon wafer are exposed with different exposure doses and different focal plane positions; wherein, the second test silicon wafer includes a second preset number of exposure areas, and each of the exposure areas includes an exposure pattern that corresponds one-to-one with the marked pattern in the second phase-shift mask and has a phase-shift error;

[0022] The phase shift error of each marker pattern in each of the exposure areas is detected, and the relationship curve between the phase shift error of each marker pattern and the focal plane position under the same exposure dose is fitted to obtain the slope of the fitted line.

[0023] Fit the curves of the relationship between slope and exposure dose for different marked patterns;

[0024] A preset range of exposure dose is determined in the curve relating slope and exposure dose, in which the slope and exposure dose are linearly related and the slope of the fitted line is a.

[0025] A preset exposure dose is determined within the preset range.

[0026] Optionally, the exposure area of ​​the second test silicon wafer is smaller than the exposure area of ​​the first test silicon wafer, and both the first preset number of exposure areas and the second preset number of exposure areas are arranged in multiple rows and columns, with the number of rows and columns of the first preset number of exposure areas being greater than the number of rows and columns of the second preset number of exposure areas, respectively.

[0027] Optionally, using the first phase-shifting mask, exposure is performed at different focal plane positions in multiple exposure areas on the first test silicon wafer according to a preset exposure dose, including:

[0028] The first phase-shift mask is adjusted to be located in the first orientation and the second orientation, respectively, and exposed on the first test silicon wafer at different focal plane positions according to the preset exposure dose; wherein, in the first orientation, the light-shielding strip in the first phase-shift mask is perpendicular to the horizontal direction in the plane where the exposure site is located; in the second orientation, the light-shielding strip in the first phase-shift mask is perpendicular to the vertical direction in the plane where the exposure site is located.

[0029] The phase shift error of each marker pattern in each exposure area is detected, and the relationship curve between the phase shift error and the focal plane position of each marker pattern is fitted to obtain the slope' of the fitted line, including:

[0030] The phase shift error of each marker pattern in each exposure area of ​​the first test silicon wafer in the first orientation and the second orientation is detected respectively. The relationship curve between the phase shift error of each marker pattern in the first orientation and the focal plane position is fitted and the slope' of the fitted straight line is obtained.

[0031] Based on the slope', the fitted linear relationship between the slope and the exposure dose Energy (Energy = a × Slope + b), and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope and the exposure dose for each marked pattern, the ordinate b' of the fitted linear relationship between the slope and the exposure dose Energy for each marked pattern is calculated, including:

[0032] Based on the slope', the fitted linear relationship between the slope and the exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope and the exposure dose for each marked pattern, the ordinate b' of the fitted linear relationship between the slope and the exposure dose Energy for each marked pattern in the first test silicon wafer of the first orientation and the second orientation is calculated.

[0033] The uniformity of slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer, including:

[0034] The horizontal uniformity of the slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer corresponding to the first orientation; the vertical uniformity of the slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer corresponding to the second orientation.

[0035] Optionally, in the first phase-shifting mask, the light-shielding strip further includes a third light-shielding strip, and at least two third light-shielding strips are spaced apart between two adjacent first light-shielding strips, and at least one third light-shielding strip is spaced apart between the first light-shielding strip and the second light-shielding strip; the width of the third light-shielding strip is equal to the width of the first light-shielding strip, and the length of the third light-shielding strip is less than the length of the first light-shielding strip;

[0036] The detection method further includes:

[0037] Following the same division method, each of the first light-shielding strips is divided into multiple light-shielding strips along the extension direction;

[0038] The phase shift error of each light-blocking strip in each marked pattern in each exposure area is detected. The relationship curve between the phase shift error of each light-blocking strip and the focal plane position is fitted, and the slope of the fitted line is obtained.

[0039] Based on the slope, the fitted linear relationship between slope and exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between slope and exposure dose for each marked pattern, calculate the ordinate b" of the fitted linear relationship between slope and exposure dose Energy for each segment of the light-shielding strip in each marked pattern.

[0040] Based on the magnitude of the ordinate b” of the fitted straight line corresponding to each segment of the light-shielding strip in each marked pattern, it is determined that there is no stray light during the exposure of the lithography machine.

[0041] In this embodiment, a first phase-shift mask and a first test silicon wafer are provided. Then, using the first phase-shift mask, exposure is performed on the first test silicon wafer at different focal plane positions according to a preset exposure dose. Subsequently, the phase shift error of each marked pattern in the first test silicon wafer corresponding to different focal plane positions is detected. The relationship curve between the phase shift error and the focal plane position of each marked pattern is fitted, and the slope' of the fitted straight line is obtained. Based on the slope', the fitted straight line relationship between the slope and the exposure dose Energy (Energy = a × Slope + b), and the known preset exposure dose Energy' and the slope a of the fitted straight line between the slope and the exposure dose for each marked pattern, the ordinate b' of the fitted straight line between the slope and the exposure dose Energy for each marked pattern is calculated. Finally, the uniformity of the slit illumination can be determined based on the dispersion of the ordinate b' of each marked pattern in the first test silicon wafer. The method for detecting the uniformity of light transmission through slits in a lithography machine provided in this invention solves the problem that existing illumination uniformity measurements can only be performed offline, enabling online illumination uniformity measurement. This method not only adapts to complex and changing actual working conditions and judges the uniformity of light transmission through slits in the lithography machine, but also quickly determines whether the vertical illumination system needs recalibration, promptly preventing yield reductions caused by illumination system malfunctions. Furthermore, replacing the original offline calibration method with a process exposure method simplifies the measurement process, improves measurement accuracy, ensures continuous production without machine downtime, saves time, reduces costs, and accurately reflects the current vertical performance of the machine. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of a phase-shifting mask provided in an embodiment of the present invention;

[0043] Figure 2 yes Figure 1 A schematic diagram of the structure of the marked pattern in the phase-shifting mask shown;

[0044] Figure 3 This is a flowchart of a method for detecting the uniformity of light transmission in a lithography machine slit, provided by an embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram of the first test silicon wafer exposure and overlay measurement provided in an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the fitting straight lines of multiple exposure areas of the first test silicon wafer provided in an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the intercept distribution provided in an embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of the uniformity distribution of slit lighting provided in an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of a point detection and measurement structure provided in an embodiment of the present invention;

[0050] Figure 9 This is a schematic diagram of the second test silicon wafer exposure and overlay measurement provided in an embodiment of the present invention;

[0051] Figure 10 This is a schematic diagram of the fitting straight lines of multiple exposure areas of the second test silicon wafer provided in an embodiment of the present invention;

[0052] Figure 11 This is a flowchart of another method for detecting the uniformity of light transmission in a lithography machine slit, provided in an embodiment of the present invention;

[0053] Figure 12 This is a schematic diagram of the structure of a marking pattern for another phase-shifting mask provided in an embodiment of the present invention;

[0054] Figure 13 This is a flowchart of another method for detecting the uniformity of light transmission in a lithography machine slit, provided in an embodiment of the present invention. Detailed Implementation

[0055] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0056] Figure 1 This is a schematic diagram of the structure of a phase-shifting mask provided in an embodiment of the present invention. Figure 2 yes Figure 1 The schematic diagram of the marked pattern in the phase-shifting mask shown is for reference. Figure 1 and Figure 2 First, the phase-shifting mask provided in this embodiment of the invention is mainly used for detecting the uniformity of light transmission in the slit of a lithography machine. Specifically, it includes multiple marking patterns 100 arranged periodically along multiple rows and columns. Each marking pattern 100 includes multiple light-shielding strips 10 arranged periodically and parallel to each other. Each light-shielding strip 10 includes a first light-shielding strip 11 and a second light-shielding strip 12. At least one second light-shielding strip 12 is spaced between two adjacent first light-shielding strips 11. A phase-shifting region 110 is provided on one or both sides of the first light-shielding strip 11.

[0057] A phase-shifting mask is a mask that not only contains mask patterns for blocking or transmitting light, but also regions that alter the phase of the transmitted light. Two beams of light transmitted through different positions on the mask pattern will interfere because they are in phase, resulting in the peaks and troughs of the two beams being in the same relative position. By adding phase-shifting regions to the mask pattern, the phase of the transmitted light can be shifted. When the focal plane shifts, the spatial image of the marked pattern shifts, ultimately forming an asymmetrical image. By measuring the overlay error of these images, the focal plane information of the lithography machine can be obtained. In other words, phase-shifting mask technology can induce a phase shift in the transmitted light beam in a specific area, causing the corresponding exposure pattern to shift due to the change in focal plane. Overlay measurements can then accurately determine the defocusing amount at each point, i.e., the overlay error or phase-shift error, which can be used to determine the focal plane position.

[0058] In this embodiment, the light-blocking strip 10 is used to block light. A phase-shifting region 110 is provided on one or both sides of the first light-blocking strip 11, which can be used to shift the phase of the transmitted light. When light passes through the gaps between multiple periodically arranged and parallel light-blocking strips 10, the phase shift caused by the phase shifting region 110 will cause a shift in the exposed image of the marking pattern when the focal plane shifts. Based on this principle, the information of the focal plane can also be determined by measuring this shift, i.e., the phase shift error. The number of first light-blocking strips 11 in the marking pattern 100 can be multiple, specifically 1, 2, 3, etc., and is not limited here.

[0059] It is understood that in this embodiment, the exposure process of the phase-shifting mask is for the silicon wafer etched by the lithography machine. Typically, a photoresist layer needs to be coated on the silicon wafer. Exposure causes the photoresist to cure, and the uncured photoresist can be removed, thus retaining the exposure pattern. This photoresist pattern can then be used to etch the silicon wafer, completing the lithography process. The phase-shifting mask provided in this embodiment is mainly used to detect the uniformity of light transmission through the slits of the lithography machine. That is, a normal exposure procedure is used to expose the silicon wafer for testing, and the uniformity is detected by the pattern information after exposure.

[0060] In this embodiment, the phase-shifting mask may include a substrate. The light-shielding strips are formed by depositing a non-transparent material, such as metallic chromium, onto the substrate and then patterning multiple light-shielding strips. The phase-shifting region can be formed by depositing silicon dioxide material onto the substrate to form a semi-transparent silicon dioxide layer, also patterned. It is understood that the material and thickness of the phase-shifting region will affect the phase shift generated when light passes through. In this embodiment, the optional phase-shifting region can cause a phase shift of π / 4 to π / 2 in the transmitted light; for example, the optional phase-shifting region can cause a phase shift of π / 2 in the transmitted light.

[0061] In one embodiment of the present invention, reference continues to... Figure 1 The first light-shielding strip 11 and the second light-shielding strip 12 can be configured to have equal lengths and widths. That is, the width d1 of the first light-shielding strip 11 and the width d2 of the second light-shielding strip 12 are equal, and the length of both the first light-shielding strip 11 and the second light-shielding strip 12 is c1. Furthermore, the first light-shielding strip 11 and the second light-shielding strip 12 can be arranged alternately at equal intervals. In addition, the distance s1 between the first light-shielding strip 11 and the second light-shielding strip 12 can be set to be equal to the width of the first light-shielding strip 11 and the second light-shielding strip 12, i.e., s1 = d1 = d2.

[0062] It is understood that the first light-shielding strip 11 and the second light-shielding strip 12 are of equal length and width and are arranged alternately at equal intervals. In this case, the light passing through the slits in the marked pattern will interfere due to phase coherence. However, by setting a phase-shifting region 110 on one or both sides of the first light-shielding strip 11, the phase of the light passing through the slits can be changed, thereby avoiding interference. Moreover, based on this, it can be ensured that when the image is focused by the lithography machine lens system, the change in focal plane corresponds to the change in defocus.

[0063] Optionally, in this embodiment of the invention, the length c1 of the first light-shielding strip 11 can be set to be greater than 4 μm. Simultaneously, optionally, the width of the phase-shifting region can be set to be equal to 1 / 8 to 1 / 2 of the distance between two adjacent light-shielding strips. In this case, the size of the marking pattern is relatively small, occupying a smaller area on the phase-shifting mask, which is beneficial for improving the utilization rate of the phase-shifting mask. For example, in this embodiment, the width of the phase-shifting region is set to be equal to 1 / 4 of the distance between two adjacent light-shielding strips. Furthermore, in this embodiment, the widths of the light-shielding strips, i.e., the width d1 of the first light-shielding strip 11 and the width d2 of the second light-shielding strip 12, can both be set to be equal to the resolution of the lithography machine.

[0064] Figure 3 This is a flowchart of a method for detecting the uniformity of light transmission in a lithography machine slit, provided by an embodiment of the present invention. The following is a reference to... Figures 1-3This paper specifically describes a method for detecting the uniformity of light transmission through a lithography slit using the phase-shifting mask provided in the above embodiments. The detection method includes:

[0065] S110, providing a first phase-shifting mask and a first test silicon wafer;

[0066] The first phase-shifting mask is mainly used for slit light transmission uniformity detection, and the marking patterns on it are specifically designed for this purpose. These marking patterns are arranged in an array, with a fixed number and arrangement. In this step, the first phase-shifting mask can have marking patterns arranged in 5 rows and 7 columns. The first test silicon wafer is a silicon wafer containing a photoresist layer to be exposed. After exposure on the first test silicon wafer, an exposure pattern corresponding to the marking patterns can be formed on the first test silicon wafer through development. The phase shift error of the exposure pattern can be used to detect light transmission uniformity.

[0067] S120. Using a first phase-shifting mask, multiple exposure areas on a first test silicon wafer are exposed at different focal plane positions according to a preset exposure dose; wherein, the first test silicon wafer includes a first preset number of exposure areas, and each exposure area includes an exposure pattern that corresponds one-to-one with the marked pattern in the first phase-shifting mask and has a phase-shifting error; the phase-shifting error of the marked pattern in all exposure areas of the first test silicon wafer is linearly related to the focal plane position, and the slope of the fitted line is slope; the slope of the same marked pattern is linearly related to the exposure dose in a preset interval, and the slope of the fitted line is a, and the preset exposure dose is located within the preset interval of exposure dose;

[0068] This step is essentially a focus matrix (FM) exposure process, which is a testing process. In this step, the exposure field of view can be selected as 26×33mm, and relevant exposure parameters, such as the focus position, need to be changed to expose multiple exposure areas of the first test silicon wafer separately, obtaining the exposed pattern. Therefore, in the first test silicon wafer, the phase shift error corresponding to the focus position can be obtained based on the exposure pattern. It should be noted that the first test silicon wafer actually contains multiple exposure areas, each corresponding to one exposure of the first phase shift mask, and the exposure pattern within each area corresponds to a marker pattern on the first phase shift mask, i.e., forming an exposure pattern of 5 rows and 7 columns within the exposure area. Furthermore, the exposure dose used in this step needs to be predetermined. Firstly, the inventors discovered in their research that for the three parameters of phase shift error, focus position, and exposure dose, there is essentially a linear relationship between the phase shift error of each marker pattern and the focus position; that is, the larger the focus position, the larger the phase shift error, and the fitted line between the phase shift error and the focus position has a fixed slope. However, the prerequisite for fixing the slope of the fitted line between the phase shift error and the focal plane position is that the exposure dose is fixed. In other words, when the exposure dose is fixed, the slope of the fitted line between the phase shift error and the focal plane position is fixed, but when the exposure dose changes, the value of the slope also changes. Based on this, the inventors further discovered that the influence of the exposure dose on the slope value also follows a pattern. By fitting the relationship curve between the exposure dose and the slope, it can be seen that within a certain exposure dose range, the exposure dose and the slope have a linear relationship, and the slope of the fitted line can be determined as 'a'. In this step, an exposure dose is determined within a preset range that satisfies the linear relationship between the exposure dose and the slope. Each first test silicon wafer is exposed with this exposure dose, and by changing only the position of the focal plane, the phase shift error corresponding to the focal plane position of each marked pattern can be obtained.

[0069] S130. Detect the phase shift error of each marker pattern in each exposure area, fit the relationship curve between the phase shift error of each marker pattern and the focal plane position, and obtain the slope' of the fitted line.

[0070] Based on the above steps, the phase shift error of each marked pattern in the first test silicon wafer corresponding to different focal plane positions is measured, and a series of data corresponding to the focal plane position and the phase shift error can be obtained. Based on this series of data, a straight line can be fitted between the phase shift error and the focal plane position corresponding to the marked pattern at the same position, and the slope' of the actual fitted straight line between the phase shift error and the focal plane position of each marked pattern can be determined.

[0071] S140. Based on the slope slope', the fitted linear relationship between the slope slope and the exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope slope and the exposure dose for each marked graphic, calculate the ordinate b' of the fitted linear relationship between the slope slope and the exposure dose Energy for each marked graphic.

[0072] This step involves substituting the actual phase shift error of each marked pattern, the slope' of the focal plane position, and the actual exposure dose into the fitted linear relationship between the slope and the exposure dose, Energy = a × Slope + b, to calculate the actual intercept b'. This process uses the known fitted linear relationship between the slope and the exposure dose, Energy = a × Slope + b, to determine the fitted line for each exposure zone. It can be understood that the closer the fitted line between the slope and the exposure dose for each exposure zone is, the more consistent the identical marked patterns formed in each exposure zone are. Therefore, this fitted line can be used to represent the light transmission uniformity of the slit.

[0073] Figure 4 This is a schematic diagram of the exposure and overlay measurement of the first test silicon wafer provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the fitting straight lines of multiple exposure areas of the first test silicon wafer provided in the embodiment of the present invention. First, refer to... Figure 4 By setting multiple exposure areas on the first test silicon wafer, the first phase-shift mask is sequentially exposed in the exposure areas, so that the 5×7 marking pattern is exposed to form a 5×7 exposure pattern (e.g., ...). Figure 4 (As shown in the magnified view), the overlay error of the exposed pattern can be measured using a micro-measuring scanning electron microscope (CD-SEM). Figure 4 The diagram shows overlay error detection performed in 21 exposure areas. Each exposure area corresponds to a 5x7 marker pattern on the first phase-shift mask, meaning that phase-shift error data for 35 marker patterns need to be collected for each exposure area. Furthermore, the value in each exposure area represents the focal plane position of that area. Therefore, for the same marker pattern (located at the same position in the 5×7 array, equal to the number of exposure areas, totaling 21) across all exposure areas, a slope' can be obtained. Clearly, a slope' can be obtained for each of the 35 marker patterns. Further, refer to... Figure 5Taking the V-direction as an example, for the marked pattern at the same position in 21 exposure zones, a total of 35 slope data points can be obtained. Based on these 21 slopes, the known preset exposure dose Energy', and the slope 'a' of the fitted line for each exposure zone, substituting them into the fitted line relationship between slope and exposure dose Energy (Energy = a × Slope + b), the fitted line between slope and exposure dose Energy for each marked pattern can be plotted (a total of 35, corresponding to...). Figure 4 (The 35 marked graphs shown). Taking multiple fitted lines with positive slopes as an example, it can be seen that although the slopes of different fitted lines are basically the same, their intercepts b' are significantly different.

[0074] S150. Determine the uniformity of slit illumination based on the dispersion of the longitudinal intercept b' of each marked pattern in the first test silicon wafer.

[0075] As can be seen from step S140 above, the closer the fitted line of slope and exposure dose Energy is, the more uniform the light transmission of the lithography machine slit is. In this embodiment of the invention, under the premise of determining the exposure dose, the slope 'a' of the fitted line of slope and exposure dose Energy is fixed. Based on the determined slope ', the intercept 'b' can be used to represent the fitted line, that is, the degree of dispersion of the intercept 'b' represents the degree of closeness of the fitted line, which can also determine the uniformity of slit illumination.

[0076] Specifically, the calculated longitudinal intercept b' of each exposure zone can be processed with 3sigma, and the result can be used as a value to evaluate the uniformity of light transmission in the current slit of the abutment. Figure 6 This is a schematic diagram of the intercept distribution provided in an embodiment of the present invention. Figure 7 This is a schematic diagram of the uniformity distribution of slit illumination provided in an embodiment of the present invention, for reference. Figure 6 and Figure 7 Taking the vertical direction (V-direction) of the exposure area in the plane as an example, the hollow mark indicates an abnormal opening position, determined by the dispersion of the longitudinal intercept b', while the solid mark indicates a normal opening position, determined by the dispersion of the longitudinal intercept b'. Through these abnormal marks, the uniformity distribution of the slit illumination in the lithography machine can be visually obtained.

[0077] Based on the method for detecting the uniformity of light transmission in the slit of a lithography machine provided in the above embodiments, this invention also provides experimental verification. By using a point detector (ESS: Energy Spot Sensor) to measure the exposure energy at different locations on the lithography machine, the uniformity of exposure energy at different locations can be determined. This invention also measured the light intensity distribution of a 26mm*13.5mm illumination field of view using this point detector. Figure 8This is a schematic diagram of a point detection and measurement structure provided in an embodiment of the present invention, for reference. Figure 8 The test results represent the light intensity uniformity under a static field of view. The results show that the slit illumination uniformity is 2.306%, and the top illumination uniformity is 3.344%. (Comparison) Figure 6 and Figure 7 As can be seen from the slit uniformity shown, the slit uniformity detection method provided in this embodiment has a similar distribution trend to the test structure of the point detector, and the abnormal point positions are consistent.

[0078] In this embodiment, a first phase-shift mask and a first test silicon wafer are provided. Then, using the first phase-shift mask, exposure is performed on the first test silicon wafer at different focal plane positions according to a preset exposure dose. Subsequently, the phase shift error of each marked pattern in the first test silicon wafer corresponding to different focal plane positions is detected. The relationship curve between the phase shift error and the focal plane position of each marked pattern is fitted, and the slope' of the fitted straight line is obtained. Based on the slope', the fitted straight line relationship between the slope and the exposure dose Energy (Energy = a × Slope + b), and the known preset exposure dose Energy' and the slope a of the fitted straight line between the slope and the exposure dose for each marked pattern, the ordinate b' of the fitted straight line between the slope and the exposure dose Energy for each marked pattern is calculated. Finally, the uniformity of the slit illumination can be determined based on the dispersion of the ordinate b' of each marked pattern in the first test silicon wafer. The method for detecting the uniformity of light transmission through slits in a lithography machine provided in this invention solves the problem that existing illumination uniformity measurements can only be performed offline, enabling online illumination uniformity measurement. This method not only adapts to complex and changing actual working conditions and judges the uniformity of light transmission through slits in the lithography machine, but also quickly determines whether the vertical illumination system needs recalibration, promptly preventing yield reductions caused by illumination system malfunctions. Furthermore, replacing the original offline calibration method with a process exposure method simplifies the measurement process, improves measurement accuracy, ensures continuous production without machine downtime, saves time, reduces costs, and accurately reflects the current vertical performance of the machine.

[0079] It is understood that in the detection method provided by the embodiments of the present invention, it is necessary to pre-measure the phase shift error under different exposure conditions (different focal plane positions and exposure doses) in the current state of the lithography machine to obtain a fitted linear relationship between the focal plane position and the phase shift error, including the slope of the focal plane position and the phase shift error. Then, a fitted curve of the slope and the exposure dose can be obtained, including the interval where the slope is not affected by the dose, and the slope 'a' of the slope and the exposure dose within that interval. At this time, for each marked pattern in the exposure area, based on the pre-measured slope 'a' and the fitted linear relationship between the slope and the exposure dose Energy (Energy = a × Slope + b), the intercept 'b' of the fitted line can be obtained. The uniformity of light transmission through the lithography machine slit is analyzed based on the intercept 'b'. Therefore, in the embodiments of the present invention, before step S120, which uses a first phase shift mask to expose multiple first test silicon wafers at different focal plane positions according to a preset exposure dose, the method further includes:

[0080] S101, providing a second phase-shifting mask and a second test silicon wafer;

[0081] The second phase-shifting mask used in this step is identical to the first phase-shifting mask used in step S110, except that the number and arrangement of the marking patterns differ. The second test silicon wafer is made of the same material as the first test silicon wafer, and its size depends on the number of marking patterns on the phase-shifting mask. Alternatively, both the first and second test silicon wafers can be larger than the exposure area of ​​both the first and second phase-shifting masks; in this case, the first and second test silicon wafers will have the same size and be indistinguishable.

[0082] S102. Using a second phase-shifting mask, different exposure areas on the second test silicon wafer are exposed with different exposure doses and different focal plane positions; wherein, the second test silicon wafer includes a second preset number of exposure areas, and each exposure area includes an exposure pattern that corresponds one-to-one with the marked pattern in the second phase-shifting mask and has a phase-shifting error.

[0083] S103. Detect the phase shift error of each marker pattern in each exposure area, fit the relationship curve between the phase shift error of each marker pattern and the focal plane position under the same exposure dose, and obtain the slope of the fitted line.

[0084] S104. Fit the curves of the relationship between slope and exposure dose for different marked graphics;

[0085] S105. Determine a preset range of exposure dose in the curve relating slope and exposure dose. In the preset range, the slope and exposure dose are linearly related, and the slope of the fitted line is a.

[0086] S106. Determine the preset exposure dose within the preset range.

[0087] The process of pre-measuring phase shift error under different exposure conditions (different focal plane positions and exposure doses) is essentially a focus-energy matrix (FEM) exposure process. That is, it is necessary to adjust different focal planes and different doses to obtain phase shift error under different exposure conditions. Figure 9 This is a schematic diagram of the second test silicon wafer exposure and overlay measurement provided in an embodiment of the present invention. Figure 10 This is a schematic diagram of the fitting straight lines of multiple exposure areas of the second test silicon wafer provided in an embodiment of the present invention, for reference. Figure 9 and Figure 10 The phase shift error can be obtained by overlay measurement of the exposure pattern formed by the focal plane matrix exposure. For the marked pattern at the same position in all exposure areas, a series of slope values ​​for phase shift error and focal plane position can be calculated based on the phase shift error and focal plane position. Then, the relationship curve between the slope and the corresponding exposure dose data can be plotted for multiple marked patterns. Figure 10 As shown, the horizontal axis represents the exposure dose (Energy), and the vertical axis represents the slope. Each curve corresponds to a marker pattern located at a different position. It can be understood that each data point on the same curve represents the phase shift error and the slope value of the focal plane position of the marker pattern at a given exposure dose. This slope value is obtained by linearly fitting the phase shift error of the marker pattern at each exposure zone, i.e., each focal plane position. Figure 10 It can be seen that within a certain exposure dose range, the slope is relatively gentle, and the change in slope within this region is not affected by dose fluctuations. Based on this, a linear relationship curve between slope and exposure dose can be fitted, and the value of the slope parameter 'a' in the fitted line Energy = a × Slope + b can be obtained.

[0088] In this step, the field of view can be optionally reduced, for example, to 10×10mm, and the number and arrangement of the corresponding exposure areas can be set to 3 rows and 3 columns. It can be understood that the process of pre-measuring the phase shift error under different exposure conditions requires determining the interval in the slope-energy fitting curve where the slope is unaffected by the dose, and determining the slope 'a' of that interval. Compared to the exposure test process used to detect the uniformity of lithography machine exposure, the number of exposure areas on the second phase shift mask can be appropriately increased to ensure the accuracy of data parameters, reduce random errors, and more accurately determine the light transmission uniformity of the lithography machine slit during actual measurement.

[0089] As can be seen from the above, in this embodiment, the exposure area of ​​the second test silicon wafer can be set to be smaller than the exposure area of ​​the first test silicon wafer. The first preset number of exposure areas and the second preset number of exposure areas are both arranged in multiple rows and columns. The number of rows and columns of the first preset number of exposure areas are greater than the number of rows and columns of the second preset number of exposure areas, respectively.

[0090] The marking pattern provided in this embodiment of the invention uses light-shielding strips, with multiple strips parallel to each other. Therefore, when measuring phase shift error, it can only reflect the phase shift perpendicular to the direction of the light-shielding strips. Consequently, the detection of light transmission uniformity in lithography machines tends to focus on uniformity in the direction perpendicular to the light-shielding strips. Therefore, to better detect the light transmission uniformity of a lithography machine in different directions, based on the above embodiments, this invention also provides a method for detecting the light transmission uniformity of a lithography machine slit. Figure 11 This is a flowchart of another method for detecting the uniformity of light transmission in a lithography machine slit, provided by an embodiment of the present invention. (Refer to...) Figure 11 The detection method includes:

[0091] S210, providing a first phase-shifting mask and a first test silicon wafer;

[0092] S220. The first phase-shifting mask is adjusted to be located in the first orientation and the second orientation, respectively, and exposed on the first test silicon wafer at different focal plane positions according to the preset exposure dose; wherein, in the first orientation, the light-shielding strip in the first phase-shifting mask is perpendicular to the horizontal direction in the plane where the exposure site is located; in the second orientation, the light-shielding strip in the first phase-shifting mask is perpendicular to the vertical direction in the plane where the exposure site is located.

[0093] In this step, adjusting the first phase-shifting mask to a first orientation and a second orientation essentially involves changing the orientation of the light-shielding strips in the marked pattern on it. It can be understood that, given a fixed orientation of the light-shielding strips, the phase shift error of the measured exposure pattern is the phase shift error perpendicular to the extension direction of the light-shielding strips. By changing the orientation of the light-shielding strips, phase shift errors in two directions can be obtained. For a lithography machine, the exposure area has both horizontal and vertical orientations within the plane. In this step, the light-shielding strips can be switched to be perpendicular to either the horizontal or vertical direction within the plane of the exposure area. This allows obtaining the phase shift errors of the lithography machine in both the horizontal and vertical orientations of the exposure area plane. For example, setting the first phase-shifting mask to the first orientation, where the light-shielding strips are perpendicular to the horizontal direction within the plane of the exposure area and extend vertically, after the light-shielding strips are exposed to form the exposure pattern, the measured phase shift error is essentially the horizontal phase shift error.

[0094] S230. Detect the phase shift error of each marker pattern in each exposure area of ​​the first test silicon wafer in the first orientation and the second orientation respectively, fit the relationship curve between the phase shift error of each marker pattern in the first orientation and the focal plane position, and obtain the slope' of the fitted straight line.

[0095] This step involves fitting the relationship between the phase shift error detected under the two orientation states and the focal plane position, and is used to perform the detection steps for the two orientation states respectively.

[0096] S240. Based on the slope', the fitted linear relationship between the slope and the exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope and the exposure dose for each marked pattern, calculate the ordinate b' of the fitted linear relationship between the slope and the exposure dose Energy for each marked pattern in the first test silicon wafer of the first orientation and the second orientation.

[0097] S250. Determine the horizontal uniformity of the slit illumination based on the dispersion of the longitudinal intercept b' of each mark pattern in the first test silicon wafer corresponding to the first orientation; determine the vertical uniformity of the slit illumination based on the dispersion of the longitudinal intercept b' of each mark pattern in the first test silicon wafer corresponding to the second orientation.

[0098] By fitting the phase shift error and focal plane position relationship under the first and second orientations respectively through the above steps, and then fitting the slope' and exposure dose, the intercept b' of the fitted line of each exposure area under the two orientation states can be obtained respectively. In this way, the illumination uniformity of the lithography machine in the horizontal and vertical orientations can be obtained, thereby making a judgment on the overall illumination uniformity of the lithography machine.

[0099] The following is based on Figures 4-6 As shown, the methods for judging the exposure uniformity of two orientations are introduced. (Reference) Figures 4-6 It can be seen that after exposure using masks with two different orientations, the phase shift errors in the horizontal and vertical directions within the plane where the exposure site is located can be obtained respectively. From these errors, the fitted lines of the horizontal and vertical slopes and the exposure dose can be obtained. The exposure uniformity in both directions can be determined based on the ordinate intercept. Figure 5 The fitted lines with negative slopes show smaller intercept differences and lower dispersion, indicating that the lithography machine has better exposure uniformity in the vertical direction. For fitted lines with positive slopes, the intercept differences are larger, indicating higher dispersion, which means the lithography machine has poorer exposure uniformity in the horizontal direction.

[0100] It should be noted that in the above embodiments, switching the orientation of the first phase-shift mask aims to change the orientation of the marking pattern. This allows the same first phase-shift mask to be used, enabling separate measurements of the illumination uniformity for the two orientations. Based on this principle, in another embodiment of the present invention, two first phase-shift masks can be used, with different orientations of the light-blocking strips. These two masks can be used to measure the illumination uniformity for the two orientations separately. Alternatively, a single first phase-shift mask can be used, containing a first marking pattern and a second marking pattern with different orientations. By measuring the phase shift error of the first and second marking patterns separately, the light transmission uniformity of the two orientations of the lithography machine can also be measured separately. Specifically, the arrangement of the first and second marking patterns is not limited here.

[0101] Furthermore, when calibrating the uniformity of slit illumination in a lithography machine, i.e. during the exposure process, it is often affected by stray light, which can lead to misjudgment. In view of the problem of stray light influence, this invention provides another embodiment. Figure 12 This is a schematic diagram of the structure of a marking pattern for another phase-shifting mask provided in an embodiment of the present invention, with reference to... Figure 12 Optionally, in another embodiment of the present invention, the light-shielding strip 10 may further include a third light-shielding strip 13, and at least two third light-shielding strips 13 are spaced apart between two adjacent first light-shielding strips 11, and at least one third light-shielding strip 13 is spaced apart between the first light-shielding strip 11 and the second light-shielding strip 12; the width of the third light-shielding strip 13 is equal to the width of the first light-shielding strip 11, and the length of the third light-shielding strip 13 is less than the length of the first light-shielding strip 11.

[0102] Optionally, the length of the third light-shielding strip 13 can be selected as 1 / 2 of the length of the first light-shielding strip 11. Since the length of the third light-shielding strip 13 is shorter, the distance between the first light-shielding strip 11 and the second light-shielding strip 12 where the third light-shielding strip 13 does not extend is larger, and the distance between the third light-shielding strip 13 and the first light-shielding strip 11 or the second light-shielding strip 12 is reduced. Based on the two sizes of distance, the phase shift error of the two distances in the same marking pattern can be measured separately for the purpose of judging stray light.

[0103] Based on this, the present invention also provides a method for detecting the uniformity of light transmission in the slits of a lithography machine. Figure 13 This is a flowchart of another method for detecting the uniformity of light transmission in a lithography machine slit, provided in an embodiment of the present invention. (Refer to...) Figure 12 and Figure 13 The detection method includes:

[0104] S310 provides a first phase-shifting mask and a first test silicon wafer;

[0105] The first phase-shifting mask uses the phase-shifting mask with a third light-blocking strip provided in the above embodiment.

[0106] S320. Following the same division method, each first light-shielding strip is divided into multiple light-shielding strips along the extension direction;

[0107] This step divides the first light-shielding strip into multiple light-shielding strips, ensuring that there are two light-shielding strips with different spacing from their adjacent light-shielding strips (which could be the second or third light-shielding strip).

[0108] S330. Detect the phase shift error of each segment of the light-blocking strip in each marked pattern in each exposure area, fit the relationship curve between the phase shift error of each segment of the light-blocking strip and the focal plane position, and obtain the slope of the fitted straight line.

[0109] S340. Based on the slope, the fitted linear relationship between the slope and the exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope and the exposure dose for each marked graphic, calculate the ordinate b" of the fitted linear relationship between the slope and the exposure dose Energy for each segment of the light-shielding strip in each marked graphic.

[0110] In the two steps described above, the slope is obtained by measuring and fitting the phase shift error and focal plane position of each light-shielding strip. Then, based on the slope and the known exposure dose Energy, the longitudinal intercept b” corresponding to different light-shielding strip segments can be obtained. This longitudinal intercept b” can be used to judge stray light and slit illumination uniformity.

[0111] S350. Based on the magnitude of the longitudinal intercept b” of the fitted straight line corresponding to each segment of the light-shielding strip in each marked pattern, determine that there is no stray light during the exposure of the lithography machine.

[0112] It is understandable that the longitudinal intercept b” of different segments of the light-blocking strip in the same marking pattern should be consistent. However, when stray light is present during exposure, the impact on different segments of the light-blocking strip with different intervals from adjacent light-blocking strips will differ, resulting in different phase shift errors. This will also affect the fitting relationship between the slope” of different segments of the light-blocking strip and the exposure dose. By comparing the magnitudes of the longitudinal intercept b” of different groups of light-blocking strips, it can be determined whether the lithography machine is affected by stray light. Specifically, for example... Figure 12 As shown, the first light-shielding strip 11 can be configured to include three lines: c2, c3, and c4. That is, the same marked graphic can include three sets of light-shielding strips: c2, c3, and c4. Correspondingly, through steps S330 and S340, the intercepts b' corresponding to these three sets of light-shielding strips can be obtained, denoted as c2', c3', and c4' respectively. By comparing the intercepts c2', c3', and c4' obtained from the three sets of results, it can be determined whether stray light exists. For example, if the difference is less than 3nm, there is no stray light influence; otherwise, it exists.

[0113] In summary, this invention employs online exposure to detect the uniformity of light transmission through the slits of a lithography machine. It allows for selection of static / dynamic exposure based on actual operating conditions, and also enables adjustments to the size, number, and distribution of the exposure area, objective lens settings, exposure dose, and focal plane. Furthermore, the location and distribution of measurement points can be determined according to specific operating requirements. This invention ensures continuous production without machine downtime, thereby saving time and reducing costs.

[0114] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A phase-shifting mask, characterized in that, The phase-shifting mask is used for detecting the uniformity of light transmission in the slits of a lithography machine. It includes multiple marker patterns arranged periodically along multiple rows and columns. The marking pattern includes a plurality of periodically arranged and parallel light-shielding strips; the light-shielding strips include a first light-shielding strip and a second light-shielding strip, with at least one second light-shielding strip between two adjacent first light-shielding strips; a phase-shifting region is provided on one or both sides of the first light-shielding strip; The length and width of the first light-shielding strip and the second light-shielding strip are equal; The distance between the first light-shielding strip and the second light-shielding strip is equal to the width of the first light-shielding strip and the width of the second light-shielding strip; The widths of the first and second light-shielding strips are both equal to the resolution of the lithography machine; The width of the phase-shifting region is equal to 1 / 8 to 1 / 2 of the distance between two adjacent light-blocking strips.

2. The phase-shifting mask according to claim 1, characterized in that, The light passing through the phase shift region undergoes a phase shift of π / 4 to π / 2.

3. The phase-shifting mask according to claim 1, characterized in that, The first and second light-shielding strips are arranged alternately at equal intervals.

4. The phase-shifting mask according to claim 1, characterized in that, The length of the first light-shielding strip is greater than 4 μm.

5. The phase-shifting mask according to claim 1, characterized in that, The light-shielding strip also includes a third light-shielding strip, and at least two third light-shielding strips are spaced apart between two adjacent first light-shielding strips, and at least one third light-shielding strip is spaced apart between the first light-shielding strip and the second light-shielding strip; The width of the third light-shielding strip is equal to the width of the first light-shielding strip, and the length of the third light-shielding strip is less than the length of the first light-shielding strip.

6. A method for detecting the uniformity of light transmission in a slit of a photolithography machine, characterized in that, The detection is performed using the phase-shifting mask as described in any one of claims 1-5, and the detection method includes: Provide the first phase-shifting mask and the first test silicon wafer; Using the first phase-shift mask, multiple exposure areas on the first test silicon wafer are exposed at different focal plane positions according to a preset exposure dose. The first test silicon wafer includes a first preset number of exposure areas, and each exposure area includes an exposure pattern that corresponds one-to-one with a marker pattern in the first phase-shift mask and has a phase-shift error. The phase-shift error and focal plane position of the marker patterns in all exposure areas of the first test silicon wafer are linearly related, and the slope of the fitted line is slope. The slope of the same marker pattern is linearly related to the exposure dose within a preset interval, and the slope of the fitted line is α. The preset exposure dose is located within the preset interval of exposure doses. The phase shift error of each marker pattern in each exposure area is detected, the relationship curve between the phase shift error of each marker pattern and the focal plane position is fitted, and the slope of the fitted line is obtained. Based on the slope slope', the fitted linear relationship between the slope slope and the exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope slope and the exposure dose for each marked pattern, calculate the ordinate b' of the fitted linear relationship between the slope slope and the exposure dose Energy for each marked pattern. The uniformity of slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer.

7. The detection method according to claim 6, characterized in that, Before exposing multiple first test silicon wafers at different focal plane positions using the first phase-shift mask according to a preset exposure dose, the process further includes: Provide a second phase-shifting mask and a second test silicon wafer; Using the second phase-shift mask, different exposure areas on the second test silicon wafer are exposed with different exposure doses and different focal plane positions; wherein, the second test silicon wafer includes a second preset number of exposure areas, and each of the exposure areas includes an exposure pattern that corresponds one-to-one with the marked pattern in the second phase-shift mask and has a phase-shift error; The phase shift error of each marker pattern in each of the exposure areas is detected, and the relationship curve between the phase shift error of each marker pattern and the focal plane position under the same exposure dose is fitted to obtain the slope of the fitted line. Fit the curves of the relationship between slope and exposure dose for different marked patterns; A preset range of exposure dose is determined in the curve relating slope and exposure dose, in which the slope and exposure dose are linearly related and the slope of the fitted line is a. A preset exposure dose is determined within the preset range.

8. The detection method according to claim 7, characterized in that, The exposure area of ​​the second test silicon wafer is smaller than that of the first test silicon wafer. Both the first preset number of exposure areas and the second preset number of exposure areas are arranged in multiple rows and columns. The number of rows and columns of the first preset number of exposure areas is greater than that of the second preset number of exposure areas.

9. The detection method according to claim 6, characterized in that, Using the first phase-shift mask, exposure is performed on multiple exposure areas of the first test silicon wafer at different focal plane positions according to a preset exposure dose, including: The first phase-shift mask is adjusted to be located in the first orientation and the second orientation, respectively, and exposed on the first test silicon wafer at different focal plane positions according to the preset exposure dose; wherein, in the first orientation, the light-shielding strip in the first phase-shift mask is perpendicular to the horizontal direction in the plane where the exposure site is located; in the second orientation, the light-shielding strip in the first phase-shift mask is perpendicular to the vertical direction in the plane where the exposure site is located. The phase shift error of each marker pattern in each exposure area is detected, and the relationship curve between the phase shift error and the focal plane position of each marker pattern is fitted to obtain the slope' of the fitted line, including: The phase shift error of each marker pattern in each exposure area of ​​the first test silicon wafer in the first orientation and the second orientation is detected respectively. The relationship curve between the phase shift error of each marker pattern in the first orientation and the focal plane position is fitted and the slope' of the fitted straight line is obtained. Based on the slope', the fitted linear relationship between the slope and the exposure dose Energy (Energy = a × Slope + b), and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope and the exposure dose for each marked pattern, the ordinate b' of the fitted linear relationship between the slope and the exposure dose Energy for each marked pattern is calculated, including: Based on the slope', the fitted linear relationship between the slope and the exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between the slope and the exposure dose for each marked pattern, the ordinate b' of the fitted linear relationship between the slope and the exposure dose Energy for each marked pattern in the first test silicon wafer of the first orientation and the second orientation is calculated. The uniformity of slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer, including: The horizontal uniformity of the slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer corresponding to the first orientation; the vertical uniformity of the slit illumination is determined based on the dispersion of the longitudinal intercept b' of each of the marked patterns in the first test silicon wafer corresponding to the second orientation.

10. The detection method according to claim 6, characterized in that, In the first phase-shifting mask, the light-shielding strip further includes a third light-shielding strip, and at least two third light-shielding strips are spaced apart between two adjacent first light-shielding strips, and at least one third light-shielding strip is spaced apart between the first light-shielding strip and the second light-shielding strip; the width of the third light-shielding strip is equal to the width of the first light-shielding strip, and the length of the third light-shielding strip is less than the length of the first light-shielding strip; The detection method further includes: Following the same division method, each of the first light-shielding strips is divided into multiple light-shielding strips along the extension direction; The phase shift error of each light-blocking strip in each marked pattern in each exposure area is detected. The relationship curve between the phase shift error of each light-blocking strip and the focal plane position is fitted, and the slope of the fitted line is obtained. Based on the slope, the fitted linear relationship between slope and exposure dose Energy = a × Slope + b, and the known preset exposure dose Energy' and the slope a of the fitted linear relationship between slope and exposure dose for each marked pattern, calculate the ordinate b" of the fitted linear relationship between slope and exposure dose Energy for each segment of the light-shielding strip in each marked pattern. Based on the magnitude of the ordinate b” of the fitted straight line corresponding to each segment of the light-shielding strip in each marked pattern, it is determined that there is no stray light during the exposure of the lithography machine.

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