Online detection method, device, medium, equipment and system for image difference of projection objective of photoetching machine

Abstract

The invention provides a photoetching machine projection objective image difference online detection method, device, medium, equipment and system. The method comprises the following steps: receiving current first optical information, current second optical information, current third optical information and current fourth optical information; and determining the actual vertical axis aberration of the projection objective according to the current first optical information, the current second optical information, the current third optical information, the current fourth optical information and the equipment parameter information. The problems that in the prior art, detection steps are complex, time is consumed, and cost is high are solved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor chip lithography, and in particular to an online detection method, device, medium, equipment and system for image aberration of a projection object of a lithography machine. Background Art

[0002] In the manufacturing process of integrated circuits, photolithography plays a vital role. It is responsible for accurately transferring the layout information of the integrated circuit to the photoresist on the silicon wafer through the mask. This process relies on the exposure of the light beam to the photoresist to achieve the transfer of the pattern. When the light beam passes through the mask, part of the light will penetrate, while the other part will be blocked, thus forming the outline of the mask pattern on the photoresist. The photoresist will undergo a photochemical reaction under the irradiation of light, while the unexposed part will remain intact, so that the pattern of the mask is accurately transferred to the photoresist. The projection lithography machine uses an imaging method to project the pattern of the mask onto the photoresist through the projection objective lens, thereby realizing the precise exposure of the photoresist. In order to accurately project and expose the pattern on the mask into the photoresist, the projection lithography machine requires a series of complex systems to work together. Among them, the role of the projection objective system is very important. The system can image the pattern on the mask onto the surface of the silicon wafer with high fidelity. As the core component of the equipment, the working performance of the projection objective seriously affects the quality of imaging, so it is necessary to regularly pay attention to whether its performance has changed (such as distortion).

[0003] In the prior art, exposure can be performed through a specific pattern mask, the developed pattern can be measured, and the measurement results can be compared with the ideal data to determine the performance change of the projection lens. However, this process includes complex operations such as gluing, developing, baking, and exposure, which often takes several hours, and the testing cost is high because actual production materials need to be used for testing.

[0004] It can be seen that the existing technology has the problems of complex detection steps, time-consuming and high cost. Summary of the invention

[0005] The present invention provides a method, device, medium, equipment and system for online detection of image aberration of a projection object of a lithography machine, which solves the problems in the prior art of complex, time-consuming and high-cost detection steps.

[0006] The present invention provides an online detection method for image aberration of a projection objective of a lithography machine, comprising: receiving current first light information, current second light information, current third light information and current fourth light information; wherein the current first light information comprises current amplitude information and current light intensity information of any coordinate in a first area of ​​a grating pattern formed after light is irradiated through a mask pattern, the current second light information comprises current amplitude information and current light intensity information of any coordinate in a second area of ​​the grating pattern formed after light is irradiated through the mask pattern, the current third light information comprises current amplitude information and current light intensity information of any coordinate in a third area of ​​the grating pattern formed after light is irradiated through the mask pattern, and the current fourth light information comprises current amplitude information and current light intensity information of any coordinate in a fourth area of ​​the grating pattern formed after light is irradiated through the mask pattern; The actual vertical axis aberration of the projection objective is determined according to the current first light information, the current second light information, the current third light information, the current fourth light information and the device parameter information.

[0007] The present invention can utilize a mask with a special pattern and calculate the actual vertical axis aberration of the projection objective by collecting amplitude information and light intensity information of different areas of the grating pattern. This not only avoids complicated actual operations such as gluing, developing, baking, and exposing, saves production materials, reduces detection costs, but also greatly saves detection time and improves detection efficiency.

[0008] Optionally, determining an actual vertical axis aberration of a projection objective lens according to current first light information, current second light information, current third light information, current fourth light information, and device parameter information includes: The current phase information is calculated according to the current first light information, the current second light information, the current third light information, and the current fourth light information; the current phase information represents the actual wavefront phase distribution of the current projection light; According to the current phase information and the corresponding device parameter information, the current vertical axis aberration of the projection objective lens at the current position is calculated; Control the movement of the workpiece stage according to the current phase information and the reference phase information; Acquire current phase information after the movement and determine the current vertical axis aberration after the movement according to the current phase information after the movement and corresponding device parameter information; The actual vertical axis aberration of the projection objective is determined based on the vertical axis aberrations at multiple different positions.

[0009] Optionally, the amplitude information characterizes the modulation depth of the grating pattern. The current phase information is calculated based on the current first light information, the current second light information, the current third light information, and the current fourth light information, and is specifically calculated using the following formula: ; in: ; ; ; ; Among them, tanφ is the current phase information; I 0 (x, y) represents the light intensity information of any coordinate in the first area; I 1 (x, y) represents the light intensity information of any coordinate in the second area, I 2 (x, y) represents the light intensity information of any coordinate in the third region, I 3 (x, y) represents the light intensity information of any coordinate in the first area; I b Characterizes the background light intensity of the grating pattern, I a The modulation depth of the grating pattern is characterized.

[0010] Optionally, the device parameter information includes system focal length, incident beam height, incident beam wavelength, and radial distance of the optical axis from the measurement point; According to the current phase information and the corresponding device parameter information, the current vertical axis aberration of the projection objective lens at the current position is calculated according to the following formula: ; ; ; Wherein, Δβ represents the magnification difference, Δr represents the distortion, ΔS represents the coma value, f represents the focal length of the system, h represents the height of the incident beam, r represents the radial distance from the optical axis to the measurement point, and λ represents the wavelength of the incident beam.

[0011] Optionally, the workpiece stage is controlled to move according to the current phase information and the reference phase information, including: According to the current phase information and the reference phase information, the target phase difference information is obtained; The workpiece stage is controlled to move to the target position according to the target phase difference information.

[0012] Optionally, the target phase difference information is obtained by calculating according to the following formula based on the current phase information and the reference phase information: ; in, is the target phase difference information, X is the reference phase information, and the reference phase information is a preset constant value.

[0013] Optionally, the actual vertical axis aberration of the projection objective is determined according to the vertical axis aberrations at multiple different positions, specifically: Determining whether the second vertical axis aberration among the three adjacent vertical axis aberrations is the minimum value among the three adjacent vertical axis aberrations; If the judgment result is yes, the second vertical axis aberration is determined to be the actual vertical axis aberration of the projection objective.

[0014] Optionally, the pattern of the mask plate is a coaxially distributed rectangular ring array; The grating pattern formed after light is irradiated through the mask pattern has a first region, a second region, a third region and a fourth region adjacent to each other, wherein the first region is arranged opposite to the third region, and the second region is arranged opposite to the fourth region.

[0015] The present invention also provides an online detection device for an image aberration of a projection objective of a lithography machine, comprising an information receiving module for receiving current first light information, current second light information, current third light information and current fourth light information; The actual aberration determination module is used to determine the actual vertical axis aberration of the projection objective lens according to the current first light information, the current second light information, the current third light information, the current fourth light information and the device parameter information.

[0016] The present invention also provides an electronic device, comprising a processor and a memory. Memory, used to store code and related data; The processor is used to execute the code in the memory for the methods of the above embodiments and possible implementation methods.

[0017] The present invention also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method of implementing the above embodiments and possible implementation methods is implemented.

[0018] The present invention also provides an online detection system for the aberration of the projection objective of a lithography machine, comprising a workpiece stage, an imaging device, a light source and a mask; The workpiece table is provided with a mounting groove, the imaging device is embedded in the mounting groove, the imaging device is provided with a photosensitive chip, and the light source projects the pattern of the mask onto the photosensitive chip through the projection objective lens to be detected; The pattern of the mask is a coaxially distributed rectangular ring array. After the diagonals of each rectangular ring are connected, the rectangular ring array is divided into a first plate area, a second plate area, a third plate area and a fourth plate area. The first plate area and the third plate area are arranged opposite to each other, and the second plate area and the fourth plate area are arranged opposite to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1a It is a structural schematic diagram of an online detection system for an image aberration of a projection objective of a lithography machine according to an embodiment of the present invention; Figure 1b It is a schematic diagram of the local enlarged structure of area A in Figure 1; Figure 2a is a schematic structural diagram of a pattern of a mask according to an embodiment of the present invention; Figure 2b It is a schematic structural diagram of a grating pattern formed after light is irradiated through a mask according to an embodiment of the present invention; Figure 3 Schematic diagram 1 of the process of the online detection method of the image aberration of the projection objective of the lithography machine according to the embodiment of the present invention; Figure 4 Schematic diagram 2 of the process of the online detection method of the image aberration of the projection objective of the lithography machine according to the embodiment of the present invention; Figure 5 Schematic diagram of the process of the on-line detection method of the projection objective aberration of the lithography machine according to the embodiment of the present invention Figure 3 ; Figure 6 Schematic diagram of the process of the on-line detection method of the projection objective aberration of the lithography machine according to the embodiment of the present invention Figure 4 ; Figure 7a Schematic diagram 1 of imaging after the workpiece stage moves in the method for online detection of objective lens aberration in a lithography machine according to an embodiment of the present invention; Figure 7b Schematic diagram 2 of imaging after the workpiece stage moves in the method for online detection of objective lens aberration in a lithography machine according to an embodiment of the present invention; Figure 7c The imaging diagram of the on-line detection method for the objective lens aberration of the lithography machine according to the embodiment of the present invention after the workpiece stage moves Figure 3 ; Figure 7d The imaging diagram of the on-line detection method for the objective lens aberration of the lithography machine according to the embodiment of the present invention after the workpiece stage moves Figure 4 ; Figure 8 Schematic diagram of the process of the on-line detection method of the projection objective aberration of the lithography machine according to the embodiment of the present invention Figure 5 ; Fig. 9 Schematic diagram of the working process of the method for online detection of the image aberration of the projection objective of the lithography machine according to the embodiment of the present invention; Fig.10 It is a structural schematic diagram of an online detection device for image aberration of a projection objective of a lithography machine according to an embodiment of the present invention; Fig.11 It is a structural schematic diagram of an electronic device according to an embodiment of the present invention; Description of reference numerals: 1: On-line detection system for the image aberration of the lithography machine projection object; 10: projection objective lens; 11: mask plate; 111: first plate area; 112: second plate area; 113: third plate area; 114: fourth plate area; 12: workpiece stage; 120: mounting slot; 13: imaging device; 131: photosensitive chip; 14: workpiece stage base. DETAILED DESCRIPTION

[0020] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0021] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0022] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0024] In the description of this embodiment, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] The present invention provides an online detection system 1 for detecting an aberration of an objective lens projection of a lithography machine, as shown in FIG. Figure 2b As shown, it includes a workpiece stage 12, an imaging device 13, a light source (not shown in the figure) and a mask 11.

[0027] The work stage 12 is provided with a mounting groove 120, and the imaging device 13 is embedded in the mounting groove 120. The imaging device 13 is provided with a photosensitive chip 131. The light source projects the pattern of the mask 11 onto the photosensitive chip 131 through the projection lens 10 to be detected. In one embodiment, the work stage 12 can be installed on the work stage base 14, for example.

[0028] The specific shape of the mask 11 can be, for example, Figure 2a As shown, the pattern of the mask 11 is a coaxially distributed rectangular ring array, and the diagonal lines of each rectangular ring are connected to divide the rectangular ring array into a first plate area 111, a second plate area 112, a third plate area 113 and a fourth plate area 114. The first plate area 111 and the third plate area 113 are arranged opposite to each other, and the second plate area 112 and the fourth plate area 114 are arranged opposite to each other.

[0029] Those skilled in the art can understand that the photosensitive chip 131 is used to receive light information and send it to the processor (or controller). The light source projects the pattern of the mask 11 onto the photosensitive chip 131 through the projection lens 10 to be detected. Figure 2b It is a grating pattern formed on the photosensitive chip 131 in an embodiment, and the grating pattern includes a first area A corresponding to the first area 111 of the mask plate 11, a second area B corresponding to the second area 112 of the mask plate 11, a third area C corresponding to the third area 113 of the mask plate, and a fourth area D corresponding to the fourth area 114 of the mask plate 11.

[0030] The present invention provides a method for detecting a projection objective lens online by using the above-mentioned online detection system 1 for detecting an aberration of a projection objective lens of a lithography machine, such as Figure 3 As shown, specifically including: Step S1: receiving current first light information, current second light information, current third light information and current fourth light information.

[0031] The current first light information includes the current amplitude information and the current light intensity information of any coordinate in the first area of ​​the grating pattern formed after the light is irradiated through the mask pattern, the current second light information includes the current amplitude information and the current light intensity information of any coordinate in the second area of ​​the grating pattern formed after the light is irradiated through the mask pattern, the current third light information includes the current amplitude information and the current light intensity information of any coordinate in the third area of ​​the grating pattern formed after the light is irradiated through the mask pattern, and the current fourth light information includes the current amplitude information and the current light intensity information of any coordinate in the fourth area of ​​the grating pattern formed after the light is irradiated through the mask pattern; Step S2: determining the actual vertical axis aberration of the projection objective lens according to the current first light information, the current second light information, the current third light information, the current fourth light information and the device parameter information.

[0032] The present invention can utilize a mask with a special pattern and calculate the actual vertical axis aberration of the projection objective by collecting amplitude information and light intensity information of different areas of the grating pattern. This not only avoids complicated actual operations such as gluing, developing, baking, and exposing, saves production materials, reduces detection costs, but also greatly saves detection time and improves detection efficiency.

[0033] In one embodiment, the pattern of the mask plate is a coaxially distributed rectangular ring array (as described above). Figure 2a Related content), the grating pattern formed after the light is irradiated through the mask pattern (such as Figure 2b As shown in the figure, the device has a first region A, a second region B, a third region C and a fourth region D which are adjacent to each other, wherein the first region A and the third region C are arranged opposite to each other, and the second region B and the fourth region D are arranged opposite to each other.

[0034] In one embodiment, the pattern size of the mask is the same as the standard exposure size, and the line width L=R / β, where R is the analytical design value of the projection lens, and β is the magnification of the projection lens.

[0035] Further, such as Figure 4 As shown, step S2 specifically includes: Step S21: Calculate current phase information according to the current first light information, the current second light information, the current third light information, and the current fourth light information; the current phase information represents the actual wavefront phase distribution of the current projection light.

[0036] Step S22: Calculate the current vertical axis aberration of the projection objective lens at the current position according to the current phase information and the corresponding device parameter information.

[0037] Step S23: Control the movement of the workpiece stage according to the current phase information and the reference phase information.

[0038] Step S24: obtaining the current phase information after the movement and determining the current vertical axis aberration after the movement according to the current phase information after the movement and the corresponding device parameter information.

[0039] Step S25: determining the actual vertical axis aberration of the projection objective lens according to the vertical axis aberrations at multiple different positions.

[0040] In one implementation, the amplitude information in step S21 represents the modulation depth of the grating pattern, and thus, the current phase information may be calculated according to the following formula: ; in: ; ; ; ; Among them, tanφ is the current phase information; I 0 (x, y) represents the light intensity information of any coordinate in the first area A; I 1 (x, y) represents the light intensity information of any coordinate in the second area B, I 2 (x, y) represents the light intensity information of any coordinate in the third area C, I 3 (x, y) represents the light intensity information of any coordinate in the first area D.

[0041] I b Characterizes the background light intensity of the grating pattern, I a The modulation depth of the grating pattern is characterized.

[0042] The following will I 0 (x,y) is simplified to I 0 , will I 1 (x,y) is simplified to I 1 , will I 2 (x,y) is simplified to I 2 , will I 3 (x,y)I 3 , simplify Ia(x, y) to I a , I b (x, y) simplifies to I b , simply deduce the above formula.

[0043] Expanding the four strength equations, we get: I 0 =I b +I a cos ; I 1 =I b +I a cos( +π / 2)=I b -I a sin ; I 2 =I b +I a cos( +π)=I b -I a cos ; I 3 =I b +I a cos( +3π / 2)=Ib +I a sin ; Substituting into the above formula we get: tan =(I 3 -I 1 ) / (I 0 -I 2 ) = (2Iasin ) / (2Iacos ) = sin / cos = tan .

[0044] It will be understood by those skilled in the art that a Characterizes the modulation depth of the grating pattern (i.e., the ratio of the modulation signal to the carrier signal amplitude), I a Multiplying by the cosine term can convert the amplitude information into light intensity information, so I 0 ,I 1 ,I 2 ,I 3 The final expression is still the light intensity. a Multiplying by the cosine term can simply deduce the process of converting amplitude information into light intensity information.

[0045] The electric field of a single light wave can be expressed as: E = A·cos(ωt - kx + θ), where A is the amplitude, ω is the angular frequency, k is the wave number, and θ is the initial phase.

[0046] When two beams of light overlap (the basic case of interference): the electric field of the first beam of light can be expressed as E 1 = A 1 ·cos(ωt- kx + θ 1 ), the electric field of the second light beam can be expressed as E 2 = A 2 ·cos(ωt - kx + θ 2 ), the total electric field is: E = E1+E2, and the superimposed light intensity is proportional to the time average of the square of the electric field, that is: Light Intensity I = = .

[0047] Among them, E 1 E 2 = , after transforming the trigonometric identity cos(a)cos(b)= [cos(a+b) + cos(ab)] / 2, we get .

[0048] Then we get the interference formula, the intensity of the first beam is I 1 =kA 1 2 / 2, the intensity of the second beam is I 2 =kA 2 2 / 2, phase difference The total light intensity is Among them, I 1 +I 2 Characterize the background light intensity, Characterize the modulation depth, from which we can get the above formula total light intensity = background light intensity I b +Modulation Depth I a × .

[0049] It can be seen that the present invention converts the background light intensity I b and modulation depth I a All of them are eliminated, and what is finally obtained is pure angle information (or phase information), realizing the conversion from light intensity measurement to phase extraction, that is, the pure phase information is cleverly extracted through the light intensity information and amplitude information of the four different areas of the grating pattern, and the workpiece stage can be guided to move (including the moving angle and moving distance) according to the phase information to eliminate the deviation between the photosensitive chip and the grating pattern (or can be understood as the position error of the workpiece stage). If the position error of the workpiece stage is not eliminated, the vertical axis aberration calculated by the phase information contains the deviation of the inaccurate position of the photosensitive chip, which will make the vertical axis aberration inaccurate, that is, deviate from the actual vertical axis aberration.

[0050] In step S22, the device parameter information includes the system focal length, the incident light beam height, the incident light beam wavelength, and the radial distance of the optical axis from the measurement point. Then, the current vertical axis aberration of the projection objective lens at the current position can be calculated according to the following formula: ; ; ; Wherein, Δβ represents the magnification difference, Δr represents the distortion, ΔS represents the coma value, f represents the focal length of the system, h represents the height of the incident beam, r represents the radial distance from the optical axis to the measurement point, and λ represents the wavelength of the incident beam.

[0051] Further, such as Figure 5 As shown, step S23 specifically includes: Step S231: Obtain target phase difference information according to current phase information and reference phase information; Step S232: Control the workpiece stage to move to the target position according to the target phase difference information.

[0052] Specifically, according to the current phase information and the reference phase information, the target phase difference information is calculated according to the following formula: ; in, is the target phase difference information, X is the reference phase information, and the reference phase information X is a preset constant. The reference phase information X can be, for example, the ideal wavefront phase, and the current phase information can be understood as the actual wavefront phase. The difference between the two is used to obtain the aberration distribution, that is, aberration = actual wavefront phase - ideal wavefront phase. The above formula Expresses the aberration in units of wavelength, which is the actual distance the stage needs to move.

[0053] Further, such as Figure 6 As shown, step S25 specifically includes: Step S251: determining whether the second vertical axis aberration among three adjacent vertical axis aberrations is the minimum value among the three adjacent vertical axis aberrations.

[0054] If the judgment result of step S251 is yes, then step S252 is executed: determine that the second vertical axis aberration is the actual vertical axis aberration of the projection objective lens. In one embodiment, see Figure 7, if the judgment result of step S251 is no, then continue to move the workpiece stage and obtain the current vertical axis aberration after the movement.

[0055] Among them, step S251 and step S252 can be understood as that the calculation result of the current vertical axis aberration will have a process of changing from large to small and then from small to large. At this time, we return the workpiece stage to the position with the smallest aberration and believe that the detected aberration has eliminated the position error.

[0056] The process of moving the workpiece stage can be understood as the process of eliminating the position error between the photosensitive chip and the grating pattern, or it can be understood as the process of eliminating the position error between the photosensitive chip and the projection lens. Figure 7a~Figure 7d , an example is given to illustrate the changes in the imaging on the photosensitive chip during the movement of the mobile workpiece stage.

[0057] in, Figure 7a The image shown shows that there is a large error between the position of the photosensitive chip and the grating pattern. The current vertical axis aberration is calculated to obtain a magnification deviation of about 2%. Figure 7b The image shown shows that there is a small error between the position of the photosensitive chip and the grating pattern. Figure 7cThe image shown is that the photosensitive chip is aligned with the projection objective lens, or it can be understood that the position error between the photosensitive chip and the grating pattern is eliminated, but the projection objective lens has aberrations. At this time, it means that the workpiece stage has moved into place. The vertical axis aberration obtained according to the phase distribution in the four areas of the grating pattern at this time is the actual vertical axis aberration of the projection objective lens (including magnification, distortion, coma, etc.). Figure 7d The imaging shown is that the photosensitive chip is aligned with the projection objective, and the projection objective has no vertical axis aberration.

[0058] It can be understood by those skilled in the art that the actual vertical-axis aberration of the projection objective detected by the above method can be zero, indicating that the performance of the projection objective is intact and does not need to be replaced. Those skilled in the art can determine the replacement threshold of the actual vertical-axis aberration according to actual production needs to take into account both production efficiency and production quality.

[0059] The following is a brief overall description of the working process of the online detection method for the image aberration of the lithography machine projection object. Figure 8 and Fig. 9 understand.

[0060] First, execute step S1, i.e. load a specific mask and expose it, so that the photosensitive chip receives the current light information of the four regions, then execute steps S21 and S22, calculate the current vertical axis aberration and current phase information of the projection objective lens, then execute steps S231 and S232, i.e. move the work stage, then execute step S24, i.e. calculate the current vertical axis aberration after each movement, then execute step S251. If the judgment result of step S251 is yes, then execute step S252. At this time, the photosensitive chip is aligned with the projection objective lens, or it can be understood that the photosensitive chip is aligned with the grating image, and the current vertical axis aberration corresponding to this position is the actual vertical axis aberration of the projection objective lens. If the judgment result of step S251 is no, then return to step S231, and continue to move the work stage until the photosensitive chip is aligned with the grating image.

[0061] In traditional technology, the distortion and magnification detection scheme must use a specific pattern mask for exposure, and measure the developed pattern to obtain the detection result, while the detection method of the present invention can obtain the detection result within 30 seconds. It can be seen that the detection system of the present invention has the advantages of high precision (better than 0.1nm), high efficiency (no exposure required), low cost (reduced silicon wafer and photoresist consumption), and can also eliminate the interference of process errors. Among them, high precision is specifically reflected in the phase calculation through the entire field, the error accumulation in the horizontal and vertical directions, and the accuracy of the calculated result is equal to the pixel size / number of pixels. By selecting a 1-micron pixel camera, if the number of pixels is 2000, an error of 0.5nm can be expressed in the full field of view, so an error of 0.1nm can be obtained.

[0062] The present invention also provides an online detection device 4 for detecting the aberration of the projection object of a lithography machine, such as Fig.10 As shown, it includes an information receiving module 41, which is used to receive the current first light information, the current second light information, the current third light information and the current fourth light information.

[0063] The actual aberration determination module 42 is used to determine the actual vertical axis aberration of the projection objective lens according to the current first light information, the current second light information, the current third light information, the current fourth light information and the device parameter information.

[0064] Please refer to Fig.11 The present invention further provides an electronic device 3, comprising: a processor 31; and A memory 33, used to store executable instructions of the processor; The processor 31 is configured to execute the above-mentioned method by executing the executable instructions. The processor 31 can communicate with the memory 33 via the bus 32 .

[0065] An embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above-mentioned method is implemented. The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for online detection of image aberration of a lithography machine projection object, applied to a controller, characterized in that: include: Receive current first light information, current second light information, current third light information, and current fourth light information; wherein the current first light information includes current amplitude information and current light intensity information of any coordinate in a first area of ​​a grating pattern formed after light is irradiated through a mask pattern, the current second light information includes current amplitude information and current light intensity information of any coordinate in a second area of ​​a grating pattern formed after light is irradiated through a mask pattern, the current third light information includes current amplitude information and current light intensity information of any coordinate in a third area of ​​a grating pattern formed after light is irradiated through a mask pattern, and the current fourth light information includes current amplitude information and current light intensity information of any coordinate in a fourth area of ​​a grating pattern formed after light is irradiated through a mask pattern; The actual vertical axis aberration of the projection objective is determined according to the current first light information, the current second light information, the current third light information, the current fourth light information and device parameter information.

2. The method for online detection of an image aberration of a lithography machine projection objective lens according to claim 1, characterized in that: The determining the actual vertical axis aberration of the projection objective lens according to the current first light information, the current second light information, the current third light information, the current fourth light information and the device parameter information comprises: The current phase information is calculated according to the current first light information, the current second light information, the current third light information, and the current fourth light information; the current phase information represents the actual wavefront phase distribution of the current projection light; Calculate the current vertical axis aberration of the projection objective lens at the current position according to the current phase information and the corresponding device parameter information; Controlling the movement of the workpiece stage according to the current phase information and the reference phase information; Acquire current phase information after the movement and determine the current vertical axis aberration after the movement according to the current phase information after the movement and corresponding device parameter information; The actual vertical axis aberration of the projection objective is determined according to the vertical axis aberrations at multiple different positions.

3. The method for online detection of image aberration of a lithography machine projection objective lens according to claim 2, characterized in that: The amplitude information characterizes the modulation depth of the grating pattern; the current phase information is calculated based on the current first light information, the current second light information, the current third light information, and the current fourth light information, and is specifically calculated by the following formula: ； in: ； ； ； ； Wherein, tanφ is the current phase information; I0 (x, y) represents the light intensity information of any coordinate in the first area; I1 (x, y) represents the light intensity information of any coordinate in the second area, I2 (x, y) represents the light intensity information of any coordinate in the third area, and I3 (x, y) represents the light intensity information of any coordinate in the first area; I b Characterizes the background light intensity of the grating pattern, I a The modulation depth of the grating pattern is characterized.

4. The method for online detection of image aberration of a lithography machine projection objective lens according to claim 3, characterized in that: The device parameter information includes system focal length, incident beam height, incident beam wavelength, and radial distance of the optical axis from the measurement point; The current vertical axis aberration of the projection objective lens at the current position is calculated based on the current phase information and the corresponding device parameter information according to the following formula: ； ； ； Wherein, Δβ represents the magnification difference, Δr represents the distortion, ΔS represents the coma value, f represents the focal length of the system, h represents the height of the incident beam, r represents the radial distance from the optical axis to the measurement point, and λ represents the wavelength of the incident beam.

5. The method for online detection of image aberration of a lithography machine projection objective lens according to claim 3, characterized in that: According to the current phase information and the reference phase information, the workpiece stage is controlled to move, including: Obtaining target phase difference information according to the current phase information and the reference phase information; The workpiece stage is controlled to move to a target position according to the target phase difference information.

6. The method for online detection of image aberration of a lithography machine projection objective lens according to claim 4, characterized in that: The target phase difference information is obtained according to the current phase information and the reference phase information by calculating according to the following formula: ； in, is the target phase difference information, X is the reference phase information, and the reference phase information is a preset constant value.

7. The method for online detection of an image aberration of a lithography machine projection objective lens according to claim 2, characterized in that: The actual vertical axis aberration of the projection objective lens is determined according to the vertical axis aberrations at multiple different positions, specifically: Determining whether a second vertical-axis aberration among three adjacent vertical-axis aberrations is a minimum value among the three adjacent vertical-axis aberrations; If the judgment result is yes, then the second vertical axis aberration is determined to be the actual vertical axis aberration of the projection objective lens.

8. The method for online detection of an image aberration of a lithography machine projection objective lens according to claim 1, characterized in that: The pattern of the mask plate is a coaxially distributed rectangular ring array; The grating pattern formed after the light is irradiated through the mask pattern has the first area, the second area, the third area and the fourth area which are adjacent to each other, wherein the first area is arranged opposite to the third area, and the second area is arranged opposite to the fourth area.

9. An online detection device for the image aberration of a projection object of a lithography machine, characterized in that: include: An information receiving module, used for receiving current first optical information, current second optical information, current third optical information and current fourth optical information; The actual aberration determination module is used to determine the actual vertical axis aberration of the projection objective lens according to the current first light information, the current second light information, the current third light information, the current fourth light information and device parameter information.

10. An electronic device, characterized in that: Including processor and memory, The memory is used to store codes and related data; The processor is used to execute the code in the memory to implement the method according to any one of claims 1 to 8.

11. A storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

12. An online detection system for the image aberration of a lithography machine projection object, characterized in that: The method according to any one of claims 1 to 8 is used for detection, comprising a workpiece stage, an imaging device, a light source and a mask; The workpiece table is provided with a mounting groove, the imaging device is embedded in the mounting groove, the imaging device is provided with a photosensitive chip, and the light source projects the pattern of the mask onto the photosensitive chip through the projection objective lens to be detected; The pattern of the mask is a coaxially distributed rectangular ring array, and the diagonal lines of each rectangular ring are connected to divide the rectangular ring array into a first plate area, a second plate area, a third plate area and a fourth plate area. The first plate area and the third plate area are arranged opposite to each other, and the second plate area and the fourth plate area are arranged opposite to each other.

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