Online Detection Method, Device, Medium, Equipment and System for Aberration of Projection Object Image of Lithography Machine

Abstract

The present invention provides a method, device, medium, equipment and system for on-line detection of aberration of a projection object mirror of a lithography machine. The method includes receiving current first optical information, current second optical information, current third optical information and current fourth optical information; determining the actual vertical aberration of the projection objective according to the current first optical information, current second optical information, current third optical information, current fourth optical information and equipment parameter information. The problems of complex detection steps, time consumption and high cost existing in the prior art are solved.

Description

Technical Field

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

[0002] In the manufacturing process of integrated circuits, a lithography machine plays a crucial role. It is responsible for accurately transferring the layout information of the integrated circuit through a mask onto the photoresist on a silicon wafer. This process relies on the exposure of the photoresist by a light beam to achieve the transfer of the pattern. When the light beam passes through the mask, some light rays will penetrate, while others will be blocked, thus forming the pattern contour of the mask on the photoresist. The photoresist undergoes a photochemical reaction under the illumination of light, and the unexposed part remains unchanged. In this way, the pattern of the mask is accurately transferred into the photoresist. A projection lithography machine projects the pattern of the mask onto the photoresist through a projection objective lens in an imaging manner, thereby achieving the accurate exposure of the photoresist. In order to accurately project and expose the pattern on the mask into the photoresist, a projection lithography machine requires a series of complex systems to work together. Among them, the role of the projection objective lens system is very important, and this 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 lens seriously affects the imaging quality, so it is necessary to regularly pay attention to whether its performance has changed (such as distortion).

[0003] In the prior art, it is possible to perform exposure through a specific pattern mask, measure the developed pattern, and compare the measurement results with ideal data to determine the performance change of the projection objective lens. However, this process includes complex operations such as coating, developing, baking, and exposure, often taking several hours, and due to the need to use actual production materials for detection, the detection cost is high.

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

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

[0006] The present invention provides an on-line detection method for the aberration of the projection object image of a lithography machine, including: receiving current first optical information, current second optical information, current third optical information, and current fourth optical information; wherein, the current first optical information includes the current amplitude information and current light intensity information of any coordinate in the first region of the grating pattern formed after the light irradiates through the mask pattern, the current second optical information includes the current amplitude information and current light intensity information of any coordinate in the second region of the grating pattern formed after the light irradiates through the mask pattern, the current third optical information includes the current amplitude information and current light intensity information of any coordinate in the third region of the grating pattern formed after the light irradiates through the mask pattern, and the current fourth optical information includes the current amplitude information and current light intensity information of any coordinate in the fourth region of the grating pattern formed after the light irradiates through the mask pattern;

[0007] Determine the actual vertical aberration of the projection objective according to the current first optical information, current second optical information, current third optical information, current fourth optical information, and equipment parameter information.

[0008] The present invention can utilize a mask with a special pattern, and calculate the actual vertical aberration of the projection objective by collecting the amplitude information and light intensity information of different regions of the grating pattern. It not only avoids complex actual operations such as coating, developing, baking, and exposure, saves production materials, reduces the detection cost, but also greatly saves the detection time and improves the detection efficiency.

[0009] Optionally, determining the actual vertical aberration of the projection objective according to the current first optical information, current second optical information, current third optical information, current fourth optical information, and equipment parameter information includes:

[0010] Calculate the current phase information according to the current first optical information, current second optical information, current third optical information, and current fourth optical information; the current phase information characterizes the actual wavefront phase distribution of the current projected light;

[0011] Calculate the current vertical aberration of the projection objective at the current position according to the current phase information and the corresponding equipment parameter information;

[0012] Control the movement of the workpiece table according to the current phase information and the reference phase information;

[0013] Obtain the current phase information after movement and determine the current vertical aberration after movement according to the current phase information after movement and the corresponding equipment parameter information;

[0014] Determine the actual vertical aberration of the projection objective according to the vertical aberrations at multiple different positions.

[0015] 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, current second light information, current third light information, and current fourth light information, specifically calculated by the following formula:

[0016] ;

[0017] Where:

[0018] ;

[0019] ;

[0020] ;

[0021] ;

[0022] where tanφ is the current phase information;

[0023] I0(x, y) characterizes the light intensity information of any coordinate in the first region; I1(x, y) characterizes the light intensity information of any coordinate in the second region, I2(x, y) characterizes the light intensity information of any coordinate in the third region, I3(x, y) characterizes the light intensity information of any coordinate in the first region;

[0024] I b characterizes the background light intensity of the grating pattern, and I a characterizes the modulation depth of the grating pattern.

[0025] Optionally, the device parameter information includes the system focal length, incident beam height, incident beam wavelength, and radial distance from the optical axis to the measurement point;

[0026] Based on the current phase information and the corresponding device parameter information, the current vertical aberration of the projection objective at the current position is calculated according to the following formula:

[0027] ;

[0028] ;

[0029] ;

[0030] where Δβ represents the magnification difference, Δr represents the distortion, and ΔS represents the coma aberration; f represents the system focal length, h represents the incident beam height, r represents the radial distance from the optical axis to the measurement point, and λ represents the incident beam wavelength.

[0031] Optionally, controlling the movement of the workpiece stage based on the current phase information and the reference phase information includes:

[0032] Obtain the target phase difference information according to the current phase information and the reference phase information;

[0033] Control the workpiece stage to move to the target position according to the target phase difference information.

[0034] Optionally, obtaining the target phase difference information according to the current phase information and the reference phase information is calculated according to the following formula:

[0035] ;

[0036] Wherein, is the target phase difference information, X is the reference phase information, and the reference phase information is a preset fixed value.

[0037] Optionally, determine the actual vertical aberration of the projection objective according to the vertical aberrations at multiple different positions, specifically:

[0038] Determine whether the second vertical aberration among three adjacent vertical aberrations is the minimum value among the three adjacent vertical aberrations;

[0039] If the judgment result is yes, determine the second vertical aberration as the actual vertical aberration of the projection objective.

[0040] Optionally, the pattern of the mask plate is a coaxial rectangular ring array;

[0041] The grating pattern formed after the light irradiates through the mask plate pattern has adjacent first region, second region, third region and fourth region, wherein, the first region and the third region are oppositely arranged, and the second region and the fourth region are oppositely arranged.

[0042] The present invention also provides an on-line detection device for the aberration of the projection objective of a lithography machine, including an information receiving module for receiving current first light information, current second light information, current third light information and current fourth light information;

[0043] An actual aberration determination module for determining the actual vertical aberration of the projection objective according to the current first light information, current second light information, current third light information, current fourth light information and equipment parameter information.

[0044] The present invention also provides an electronic device, including a processor and a memory,

[0045] The memory is used for storing codes and related data;

[0046] The processor is used for executing the codes in the memory to use the methods of the above-mentioned various embodiments and possible implementation manners.

[0047] The present invention also provides a storage medium, on which a computer program is stored. When the program is executed by a processor, the methods of the above-mentioned various embodiments and possible implementation manners are realized.

[0048] The present invention also provides an on-line detection system for the aberration of a projection object image of a lithography machine, including a worktable, an imaging device, a light source and a mask;

[0049] An installation groove is provided on the worktable, the imaging device is embedded in the installation groove, a photosensitive chip is provided on the imaging device, and the light source projects the pattern of the mask onto the photosensitive chip through a projection objective lens to be detected;

[0050] The pattern of the mask is a rectangular ring array distributed coaxially. 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 oppositely arranged, and the second plate area and the fourth plate area are oppositely arranged. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1a It is a schematic structural diagram of an on-line detection system for the aberration of a projection object image of a lithography machine according to an embodiment of the present invention;

[0052] Figure 1b It is a partial enlarged structural diagram of area A in FIG. 1;

[0053] Figure 2a It is a schematic structural diagram of the pattern of the mask according to an embodiment of the present invention;

[0054] Figure 2b It is a schematic structural diagram of a grating pattern formed after light irradiates through the mask according to an embodiment of the present invention;

[0055] Figure 3 It is a first schematic flow diagram of an on-line detection method for the aberration of a projection object image of a lithography machine according to an embodiment of the present invention;

[0056] Figure 4 It is a second schematic flow diagram of an on-line detection method for the aberration of a projection object image of a lithography machine according to an embodiment of the present invention;

[0057] Figure 5 It is a schematic flow diagram of an on-line detection method for the aberration of a projection object image of a lithography machine according to an embodiment of the present invention Figure 3 ;

[0058] Figure 6 It is a schematic flow diagram of an on-line detection method for the aberration of a projection object image of a lithography machine according to an embodiment of the present invention Figure 4 ;

[0059] Figure 7a It is a first imaging schematic diagram after the worktable moves in an on-line detection method for the aberration of a projection object image of a lithography machine according to an embodiment of the present invention;

[0060] Figure 7b Schematic diagram II of the imaging after the stage movement in the method for on-line detection of the aberration of the projection object mirror of the lithography machine according to the embodiment of the present invention;

[0061] Figure 7c Schematic diagram of the imaging after the stage movement in the method for on-line detection of the aberration of the projection object mirror of the lithography machine according to the embodiment of the present invention Figure 3 ;

[0062] Figure 7d Schematic diagram of the imaging after the stage movement in the method for on-line detection of the aberration of the projection object mirror of the lithography machine according to the embodiment of the present invention Figure 4 ;

[0063] Figure 8 Flow schematic diagram of the method for on-line detection of the aberration of the projection object mirror of the lithography machine according to the embodiment of the present invention Figure 5 ;

[0064] Figure 9 Schematic diagram of the working process of the method for on-line detection of the aberration of the projection object mirror of the lithography machine according to the embodiment of the present invention;

[0065] Figure 10 Schematic diagram of the structure of the device for on-line detection of the aberration of the projection object mirror of the lithography machine according to the embodiment of the present invention;

[0066] Figure 11 Schematic diagram of the structure of the electronic device according to the embodiment of the present invention;

[0067] Explanation of the reference numerals:

[0068] 1: On-line detection system for the aberration of the projection object mirror of the lithography machine;

[0069] 10: Projection objective lens; 11: Mask; 111: First mask area; 112: Second mask area; 113: Third mask area; 114: Fourth mask area; 12: Stage; 120: Installation groove; 13: Imaging device; 131: Photosensitive chip; 14: Stage base. Detailed implementation manners

[0070] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0071] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0072] In the description of this embodiment, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0073] The terms "first", "second", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0074] In the description of this embodiment, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "connected", "connected to" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0075] To make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the drawings.

[0076] The present invention provides an on-line detection system 1 for the aberration of the projection image of a lithography machine. As shown in FIGS. 1 to Figure 2b shown, it includes a worktable 12, an imaging device 13, a light source (not shown in the figure), and a mask 11.

[0077] An installation groove 120 is provided on the worktable 12, the imaging device 13 is embedded in the installation groove 120, a photosensitive chip 131 is provided on the imaging device 13, and the light source projects the pattern of the mask 11 onto the photosensitive chip 131 through the projection objective lens 10 to be detected. In one embodiment, the worktable 12 can be installed on the worktable base 14, for example.

[0078] Among them, the specific shape of the mask 11 can be, for example, Figure 2a shown, the pattern of the mask 11 is a rectangular ring array with coaxial distribution. After the diagonals of each rectangular ring are connected, the rectangular ring array is divided 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 oppositely, and the second plate area 112 and the fourth plate area 114 are arranged oppositely.

[0079] Those skilled in the art can understand that the photosensitive chip 131 is used to receive optical information and send it to the processor (or can be understood as a controller). The light source projects the pattern of the reticle 11 onto the photosensitive chip 131 through the projection objective 10 to be detected. Figure 2b It is the grating pattern formed on the photosensitive chip 131 in an embodiment. The grating pattern includes a first region A corresponding to the first reticle area 111 of the reticle 11, a second region B corresponding to the second reticle area 112 of the reticle 11, a third region C corresponding to the third reticle area 113 of the reticle, and a fourth region D corresponding to the fourth reticle area 114 of the reticle 11.

[0080] The present invention provides a detection method for online detecting the projection objective of a projection objective mirror aberration of a lithography machine using the above-mentioned online detection system 1, as Figure 3 shown, specifically including:

[0081] Step S1: Receive the current first optical information, current second optical information, current third optical information, and current fourth optical information.

[0082] Among them, the current first optical information includes the current amplitude information and current light intensity information of any coordinate in the first region of the grating pattern formed after the light irradiates through the reticle pattern, the current second optical information includes the current amplitude information and current light intensity information of any coordinate in the second region of the grating pattern formed after the light irradiates through the reticle pattern, the current third optical information includes the current amplitude information and current light intensity information of any coordinate in the third region of the grating pattern formed after the light irradiates through the reticle pattern, and the current fourth optical information includes the current amplitude information and current light intensity information of any coordinate in the fourth region of the grating pattern formed after the light irradiates through the reticle pattern;

[0083] Step S2: Determine the actual vertical aberration of the projection objective according to the current first optical information, current second optical information, current third optical information, current fourth optical information, and equipment parameter information.

[0084] The present invention can utilize a reticle with a special pattern, and calculate the actual vertical aberration of the projection objective by collecting the amplitude information and light intensity information of different regions of the grating pattern, which not only avoids complex actual operations such as coating, developing, baking, and exposure, saves production materials, reduces the detection cost, but also greatly saves the detection time and improves the detection efficiency.

[0085] Among them, in one embodiment, the pattern of the mask plate is a coaxial rectangular ring array (as described in the relevant content above Figure 2a ), and the grating pattern formed after the light irradiates through the reticle pattern (as Figure 2bAs shown, it has adjacent first region A, second region B, third region C, and fourth region D, where the first region A and the third region C are oppositely arranged, and the second region B and the fourth region D are oppositely arranged.

[0086] 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 objective, and β is the magnification of the projection objective.

[0087] Further, as Figure 4 shown, step S2 specifically includes:

[0088] Step S21: Calculate the current phase information based on the current first light information, current second light information, current third light information, and current fourth light information; the current phase information characterizes the actual wavefront phase distribution of the current projected light.

[0089] Step S22: Calculate the current vertical aberration of the projection objective at the current position based on the current phase information and the corresponding device parameter information.

[0090] Step S23: Control the movement of the workpiece stage based on the current phase information and the reference phase information.

[0091] Step S24: Obtain the current phase information after movement and determine the current vertical aberration after movement based on the current phase information after movement and the corresponding device parameter information.

[0092] Step S25: Determine the actual vertical aberration of the projection objective based on the vertical aberrations at multiple different positions.

[0093] Among them, in one embodiment, the amplitude information in step S21 characterizes the modulation depth of the grating pattern. Furthermore, the current phase information can be calculated according to the following formula:

[0094] ;

[0095] Where:

[0096] ;

[0097] ;

[0098] ;

[0099] ;

[0100] Where tanφ is the current phase information;

[0101] I0(x, y) represents the light intensity information of any coordinate within the first region A; I1(x, y) represents the light intensity information of any coordinate within the second region B, I2(x, y) represents the light intensity information of any coordinate within the third region C, and I3(x, y) represents the light intensity information of any coordinate within the first region D.

[0102] I b represents the background light intensity of the grating pattern, and I a represents the modulation depth of the grating pattern.

[0103] Hereinafter, I0(x, y) will be simplified to I0, I1(x, y) will be simplified to I1, I2(x, y) will be simplified to I2, I3(x, y) will be simplified to I3, and Ia(x, y) will be simplified to I a , I b (x, y) will be simplified to I b , and the above formula will be simply deduced.

[0104] Expanding the four intensity equations, we get:

[0105] I0 = I b + I a cos ;

[0106] I1 = I b + I a cos( + π / 2) = I b - I a sin ;

[0107] I2 = I b + I a cos( + π) = I b - I a cos ;

[0108] I3 = I b + I a cos( + 3π / 2) = I b + I a sin ;

[0109] Substituting into the above formula, we get:

[0110] tan = (I3 - I1) / (I0 - I2) = (2Iasin ) / (2Iacos ) = sin / cos = tan 。

[0111] Those skilled in the art can understand that I a characterizes the modulation depth of the grating pattern (i.e., the ratio of the modulation signal to the amplitude of the carrier signal). Multiplying by the cosine term can convert the amplitude information into light intensity information. Therefore, I0, I1, I2, and I3 ultimately still represent light intensity. The following is a simple derivation of the process of converting amplitude information into light intensity information by multiplying by the cosine term. a Multiplying by the cosine term can convert the amplitude information into light intensity information. a The process of converting amplitude information into light intensity information by multiplying by the cosine term is simply derived as follows.

[0112] The electric field of a single beam of light 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.

[0113] When two beams of light overlap (the basic case of interference): The electric field of the first beam of light can be expressed as E1 = A1·cos(ωt - kx + θ1), and the electric field of the second beam of light can be expressed as E2 = A2·cos(ωt - kx + θ2). The total electric field is: E = E1 + E2. The light intensity after superposition is proportional to the time average of the square of the electric field, that is:

[0114] Light intensity I = = 。

[0115] Among them, E1E2 = , after using the trigonometric identity cos(a)cos(b) = [cos(a + b) + cos(a - b)] / 2 for transformation, we get 。

[0116] Furthermore, the interference formula is obtained. The intensity of the first beam of light is I1 = kA1 2 / 2, the intensity of the second beam of light is I2 = kA2 2 / 2, the phase difference , and the total light intensity is . Among them, I1 + I2 characterizes the background light intensity, characterizes the modulation depth. From this, the total light intensity of the foregoing formula can be obtained as background light intensity I b + modulation depth I a × 。

[0117] It can be seen that the present invention converts the background light intensity I b and the modulation depth I aAll are eliminated, and what is finally obtained is pure angular information (or can be understood as phase information), realizing the conversion from light intensity measurement to phase extraction, that is: the pure phase information is skillfully extracted through the light intensity information and amplitude information of four different regions of the grating pattern. According to this phase information, the stage can be guided to move (including moving angle and moving distance) to eliminate the deviation between the photosensitive chip and the grating pattern (or can be understood as the position error of the stage). If the position error of the stage is not eliminated, the vertical aberration calculated through this phase information includes the deviation of the inaccurate position of the photosensitive chip, which will make the vertical aberration inaccurate, that is, deviate from the actual vertical aberration.

[0118] Among them, in step S22, the device parameter information includes the system focal length, the height of the incident beam, the wavelength of the incident beam, and the radial distance from the optical axis to the measurement point. Furthermore, the current vertical aberration of the projection objective at the current position can be calculated according to the following formula:

[0119] ;

[0120] ;

[0121] ;

[0122] Among them, Δβ represents the magnification difference, Δr represents the distortion, and ΔS represents the coma aberration; f represents the system focal length, 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.

[0123] Furthermore, as Figure 5 shown, step S23 specifically includes:

[0124] Step S231: Obtain the target phase difference information according to the current phase information and the reference phase information;

[0125] Step S232: Control the stage to move to the target position according to the target phase difference information.

[0126] Specifically, obtaining the target phase difference information according to the current phase information and the reference phase information is calculated according to the following formula:

[0127] ;

[0128] Among them, is the target phase difference information, X is the reference phase information, and the reference phase information X is a preset fixed value. The reference phase information X can be, for example, the ideal wavefront phase. The current phase information can be understood as the actual wavefront phase. The difference between the two gives the aberration distribution, that is: aberration = actual wavefront phase - ideal wavefront phase. The above formula Indicates the aberration in units of wavelength, which is the actual distance that the worktable needs to move.

[0129] Further, as Figure 6 shown, step S25 specifically includes:

[0130] Step S251: Determine whether the second lateral aberration among three adjacent lateral aberrations is the minimum value among the three adjacent lateral aberrations.

[0131] If the judgment result of step S251 is yes, then execute step S252: Determine that the second lateral aberration is the actual lateral aberration of the projection objective. In one embodiment, please refer to FIG. 7. If the judgment result of step S251 is no, then continue to move the worktable and obtain the current lateral aberration after the movement.

[0132] Among them, steps S251 and S252 can be understood as follows: The calculation result of the current lateral aberration will have a process of changing from large to small and then from small to large. At this time, when we return the worktable to the position with the minimum aberration, it is considered that the detected aberration has excluded the position error.

[0133] The process of moving the worktable can be understood as a process of eliminating the position error between the photosensitive chip and the grating pattern, or can be understood as a process of eliminating the position error between the photosensitive chip and the projection objective. Please refer to Figure 7a to Figure 7d , which illustrates the change of the image formed on the photosensitive chip during the movement of the worktable.

[0134] Among them, Figure 7a shows that the image formed has a large position error between the photosensitive chip and the grating pattern, and the calculated current lateral aberration results in a magnification deviation of about 2%. Figure 7b shows that the image formed has a small position error between the photosensitive chip and the grating pattern. Figure 7c shows that the photosensitive chip is aligned with the projection objective, or can be understood as eliminating the position error between the photosensitive chip and the grating pattern, but there is aberration in the projection objective. At this time, it indicates that the worktable has moved in place, and the lateral aberration obtained according to the phase distribution in the four regions of the grating pattern at this time is the actual lateral aberration of the projection objective (including magnification, distortion, coma, etc.). Figure 7d shows that the photosensitive chip is aligned with the projection objective and there is no lateral aberration in the projection objective.

[0135] Those skilled in the art can understand that the actual lateral 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 lateral aberration according to actual production needs to balance production efficiency and production quality.

[0136] The working process of the following on-line detection method for the aberration of the projection objective of the lithography machine will be briefly described as a whole. Please refer toFigure 8 and Figure 9 Understand.

[0137] First, step S1 is executed, that is, a specific mask is loaded and exposed, so that the photosensitive chip receives the current optical information of four regions. Then, steps S21 and S22 are executed to calculate the current vertical aberration and the current phase information of the projection objective. Then, steps S231 and S232 are executed, that is, the workpiece stage is moved. Then, step S24 is executed, that is, the current vertical aberration after each movement is calculated. Then, step S251 is executed. If the judgment result of step S251 is yes, then step S252 is executed. At this time, the photosensitive chip is aligned with the projection objective, or it can be understood that the photosensitive chip is aligned with the grating image. The current vertical aberration corresponding to this position is the actual vertical aberration of the projection objective. If the judgment result of step S251 is no, then return to step S231 and continue to move the workpiece stage until the photosensitive chip is aligned with the grating image.

[0138] In the traditional technology, the detection schemes for distortion and magnification must use a specific pattern mask for exposure and measure the developed pattern to obtain the detection result. However, 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 0.1 nm), high efficiency (without exposure), and low cost (reducing the consumption of silicon wafers and photoresists), and can also eliminate the interference of process errors. Among them, the high precision is specifically reflected in that the phase calculation is performed throughout the field, and the errors in the horizontal and vertical directions are accumulated. The accuracy of the calculated result is equal to the pixel size / the number of pixels. By selecting a 1-micron pixel camera, such as a camera with 2000 pixels, an error of 0.5 nm can be expressed within the entire field of view, so an error of 0.1 nm can be obtained.

[0139] The present invention also provides an on-line detection device 4 for the aberration of a projection objective of a lithography machine, as Figure 10 shown, including an information receiving module 41 for receiving the current first optical information, the current second optical information, the current third optical information, and the current fourth optical information.

[0140] An actual aberration determination module 42 for determining the actual vertical 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 device parameter information.

[0141] Please refer to Figure 11 , the present invention also provides an electronic device 3, including:

[0142] A processor 31; and,

[0143] A memory 33 for storing the executable instructions of the processor;

[0144] Wherein, the processor 31 is configured to execute the above-mentioned methods by executing the executable instructions.

[0145] The processor 31 can communicate with the memory 33 through the bus 32.

[0146] An embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the above-mentioned methods are implemented.

[0147] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention 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 protection scope 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; Determine an actual vertical axis aberration of a 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; 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; Determining the actual vertical axis aberration of the projection objective lens according to the vertical axis aberrations at multiple different positions; 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.

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 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.

3. The method for online detection of an image aberration of a lithography machine projection objective lens according to claim 1, 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.

4. The method for online detection of an image aberration of a lithography machine projection objective lens according to claim 2, 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.

5. The method for online detection of an image aberration of a lithography machine projection objective lens according to claim 1, 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.

6. 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 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.

7. An online detection device for the image aberration of a projection object of a lithography machine, characterized in that: Executing any of the methods of claims 1 to 6, comprising: 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.

8. 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 6.

9. 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 6 is implemented.

10. 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 6 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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