Position measuring device, position measuring method and exposure equipment

Abstract

The invention provides a position measurement device, a measurement method, a workpiece stage position compensation method, an exposure method and exposure equipment, and the measurement device comprises a first reflector, a second reflector, a first interferometer reference axis, a second interferometer reference axis and a data processing module. The first reflecting mirror and the second reflecting mirror are arranged at the bottom of the objective lens; the first interferometer reference axis is configured to measure a first horizontal displacement of the objective lens; a second interferometer reference axis configured to measure a second horizontal displacement of the objective lens; the data processing module is configured to determine the deflection angle of the objective lens according to the first horizontal displacement and the second horizontal displacement of the objective lens and the height difference between the first interferometer reference axis and the second interferometer reference axis. According to the invention, the deflection angle of the objective lens can be measured, so that errors caused by deflection of the objective lens can be compensated to the position of the workpiece table, and the influence of the position offset of the objective lens on the overlay precision can be reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing and manufacturing technology, and in particular to a position measuring device, a measuring method, a workpiece stage position compensation method, an exposure method, and an exposure equipment. Background Technology

[0002] Exposure technology is an important micro-nano fabrication technique widely used in semiconductor manufacturing and other fields. Exposure equipment, as a crucial component of this technology, primarily functions to expose the photosensitive adhesive by focusing light onto it, thereby forming the desired pattern. During the operation of exposure equipment, real-time measurement and optimization are necessary to ensure the accuracy and stability of the exposure process.

[0003] The high-precision motion positioning of the workpiece stage in the exposure equipment is achieved by an interferometer. An interferometer is a precision optical instrument that allows for accurate detection of the height, flatness, and position of the workpiece stage, thus ensuring the accuracy of the exposure process. Utilizing the principle of light interference, the interferometer determines the position of the workpiece stage by measuring the phase difference of light waves. It features high precision and high sensitivity, making it an indispensable and crucial component of exposure equipment.

[0004] Before using an interferometer to measure the position of the workpiece stage, measurement parameters need to be set, such as the initial distance zeroing offset and measurement range. During the exposure scanning process, the workpiece stage needs to move according to the position set by the user. The interferometer processes and analyzes the interference signal data returned from the workpiece stage to calculate the precise position and other parameters of the workpiece stage in real time. The workpiece stage servo system calculates the error of the workpiece stage servo based on the position measurement results of the interferometer and compensates for the error to achieve precise positioning (ensuring that the workpiece stage moves accurately to the user-set position).

[0005] When the projection lens in an exposure device is subjected to external impact, it may tilt, causing the projected pattern to shift, resulting in projection mismatch and thus overlay error. However, current technology only considers the lens translation error and compensates for the workpiece stage position based on this error to mitigate the impact of lens position shift on overlay error. However, lens shift includes not only translation but also yaw angle. Therefore, compensating for the workpiece stage position solely based on lens translation error is insufficient to meet the high-precision overlay requirements of exposure equipment. When the lens rotates around the pupil center, current reference measurement techniques cannot measure the error caused by lens yaw, leading to projection mismatch during actual compensation.

[0006] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a position measuring device, a measuring method, a workpiece stage position compensation method, an exposure method, and an exposure equipment, which can measure the tilt angle of the objective lens, thereby compensating for the error caused by the tilt angle of the objective lens into the position of the workpiece stage, so as to reduce the impact of the objective lens position offset on the overlay accuracy of the exposure equipment.

[0008] To achieve the above objectives, the present invention provides a position measuring device, comprising a first reflecting mirror, a second reflecting mirror, a first interferometer reference axis, a second interferometer reference axis, and a data processing module. The first reflecting mirror and the second reflecting mirror are both configured to be mounted at the bottom of an objective lens, and the mounting heights of the first reflecting mirror and the second reflecting mirror at the bottom of the objective lens are different. The first interferometer reference axis is correspondingly arranged with the first reflecting mirror and is configured to measure a first horizontal displacement of the objective lens. The second interferometer reference axis is correspondingly arranged with the second reflecting mirror and is configured to measure a second horizontal displacement of the objective lens. The data processing module is configured to determine the tilt angle of the objective lens based on the first horizontal displacement and the second horizontal displacement of the objective lens, as well as the height difference between the first interferometer reference axis and the second interferometer reference axis.

[0009] Optionally, the tilt angle of the objective lens can be determined according to the following formula:

[0010]

[0011] Where ΔlensRy is the tilt angle of the objective lens, x LRA x is the first horizontal displacement of the objective lens. LRA ' is the second horizontal displacement of the objective lens, ΔH ref The height difference between the first interferometer reference axis and the second interferometer reference axis is denoted as .

[0012] Optionally, the first reflector and the second reflector are configured to be mounted on the same side of the objective lens, and the first interferometer reference axis and the second interferometer reference axis are integrated on the same interferometer.

[0013] Optionally, the first reflector and the second reflector are configured to be mounted on different sides of the objective lens, the first interferometer reference axis is disposed on the first interferometer, the second interferometer reference axis is disposed on the second interferometer, and the first interferometer and the second interferometer are configured to be disposed on different sides of the objective lens.

[0014] Optionally, the position measuring device further includes an interferometer measuring axis, which is configured to measure the horizontal displacement of the workpiece stage; the data processing module is configured to determine the projection mismatch based on the tilt angle of the objective lens and the height difference between the interferometer measuring axis and the first interferometer reference axis and / or the second interferometer reference axis, and to determine the tilt displacement of the objective lens projected onto the image plane based on the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens.

[0015] Optionally, the projection mismatch can be determined according to the following formula:

[0016]

[0017] Wherein, ΔS is the projection mismatch, ΔlensRy is the tilt angle of the objective lens, and ΔH... IFM1 The height difference ΔH between the interferometer measurement axis and the first interferometer reference axis is given by the interferometer. IFM2 The height difference between the interferometer measurement axis and the second interferometer reference axis is used.

[0018] Optionally, the yaw displacement of the objective lens projected onto the image plane can be determined according to the following formula:

[0019]

[0020] Where Δx is the yaw displacement of the objective lens projected onto the image plane, x LRA x is the first horizontal displacement of the objective lens. LRA ' represents the second horizontal displacement of the objective lens, and ΔS represents the projection mismatch.

[0021] Optionally, the interferometer measurement axis is integrated with the first interferometer reference axis and / or the second interferometer reference axis on the same interferometer.

[0022] To achieve the above objectives, the present invention also provides a method for measuring the position of an objective lens, wherein a first reflecting mirror and a second reflecting mirror are mounted at the bottom of the objective lens, and the first reflecting mirror and the second reflecting mirror are mounted at different heights at the bottom of the objective lens. The measurement method includes:

[0023] The first horizontal displacement of the objective lens is measured through the optical path between the first interferometer reference axis and the first reflecting mirror;

[0024] The second horizontal displacement of the objective lens is measured through the optical path between the second interferometer reference axis and the second reflecting mirror;

[0025] The tilt angle of the objective lens is determined based on the first horizontal displacement and the second horizontal displacement of the objective lens, as well as the height difference between the first interferometer reference axis and the second interferometer reference axis.

[0026] Optionally, the objective lens position measurement method further includes:

[0027] The projection mismatch is determined based on the tilt angle of the objective lens and the height difference between the interferometer measuring axis and the first interferometer reference axis and / or the second interferometer reference axis, wherein the interferometer measuring axis is used to measure the horizontal displacement of the workpiece stage;

[0028] The yaw displacement of the objective lens projected onto the image plane is determined based on the projection mismatch and the first and / or second horizontal displacement of the objective lens.

[0029] To achieve the above objectives, the present invention also provides a workpiece stage position compensation method, the compensation method comprising:

[0030] The tilt angle of the objective lens is determined by using the position measuring device described in any of the preceding claims or the objective lens position measuring method described in claim 9.

[0031] The projection mismatch is determined based on the tilt angle of the objective lens and the height difference between the interferometer measuring axis and the first interferometer reference axis and / or the second interferometer reference axis, wherein the interferometer measuring axis is used to measure the horizontal displacement of the workpiece stage;

[0032] The yaw displacement of the objective lens projected onto the image plane is determined based on the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens.

[0033] The correction position of the workpiece stage is determined based on the yaw displacement of the objective lens projected onto the image plane and the horizontal control position of the workpiece stage.

[0034] To achieve the above objectives, the present invention also provides an exposure apparatus, the exposure apparatus including the position measuring device described in any of the preceding claims.

[0035] To achieve the above objectives, the present invention also provides an exposure method, the exposure method comprising:

[0036] The workpiece stage position compensation method described above is used to determine the corrected position of the workpiece stage;

[0037] The workpiece stage is moved to the corrected position, and the substrate mounted on the workpiece stage is exposed.

[0038] Compared with the prior art, the position measuring device, measuring method, workpiece stage position compensation method, exposure method, and exposure equipment provided by the present invention have the following beneficial effects:

[0039] The position measuring device provided by this invention includes a first reflecting mirror, a second reflecting mirror, a first interferometer reference axis, a second interferometer reference axis, and a data processing module. Both the first and second reflecting mirrors are configured to be mounted at the bottom of the objective lens, and the mounting heights of the first and second reflecting mirrors at the bottom of the objective lens are different. The first interferometer reference axis is correspondingly arranged with the first reflecting mirror and is configured to measure the first horizontal displacement of the objective lens. The second interferometer reference axis is correspondingly arranged with the second reflecting mirror and is configured to measure the second horizontal displacement of the objective lens. The data processing module is configured to determine the tilt angle of the objective lens based on the first and second horizontal displacements of the objective lens and the height difference between the first and second interferometer reference axes. Therefore, by using the position measuring device provided by this invention, not only the horizontal displacement of the objective lens can be measured, but also the tilt angle of the objective lens can be measured. This allows for the compensation of errors caused by objective lens translation to the workpiece stage position, as well as errors caused by objective lens tilt to the workpiece stage position. Consequently, the impact of objective lens position offset on the overlay accuracy of the exposure equipment can be effectively reduced, ensuring that the substrate mounted on the workpiece stage can be exposed in the correct position, achieving the desired pattern fabrication, and improving the accuracy and reliability of the exposure process.

[0040] Since the objective lens position measurement method, workpiece stage position compensation method, exposure method, and exposure equipment provided by this invention belong to the same inventive concept as the position measurement device provided by this invention, the objective lens position measurement method, workpiece stage position compensation method, and exposure equipment provided by this invention have at least all the beneficial effects of the position measurement device provided by this invention. Therefore, the beneficial effects of the objective lens position measurement method, workpiece stage position compensation method, exposure method, and exposure equipment provided by this invention can be referred to the relevant descriptions of the beneficial effects of the position measurement device provided by this invention above, and will not be repeated here. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of an exposure device;

[0042] Figure 2 A schematic diagram of the overall structure of a position measuring device provided in one embodiment of the present invention;

[0043] Figure 3 A schematic diagram of the measurement principle of the position measuring device provided in the first embodiment of the present invention;

[0044] Figure 4 A schematic diagram of the measurement principle of a position measuring device provided in another embodiment of the present invention;

[0045] Figure 5 This is a flowchart illustrating a method for measuring the position of an objective lens according to an embodiment of the present invention.

[0046] Figure 6 This is a schematic flowchart of a workpiece stage position compensation method provided in an embodiment of the present invention;

[0047] Figure 7 This is a schematic flowchart of an exposure method provided in an embodiment of the present invention.

[0048] The accompanying figure is labeled as follows:

[0049] Illumination System - IL; Beam - B; Mask Stage - RS; Mask Plate - R; Workpiece Stage - WS; Substrate - W;

[0050] Projection lens system - PO;

[0051] First reflector -111; Second reflector -112;

[0052] First interferometer reference axis -121; Second interferometer reference axis -122;

[0053] Data processing module -130;

[0054] First interferometer measurement axis -141; Second interferometer measurement axis -142; Third interferometer measurement axis -143; Fourth interferometer measurement axis -144;

[0055] First interferometer-151; Second interferometer-152;

[0056] Objective lens-200. Detailed Implementation

[0057] The position measuring device, measuring method, workpiece stage position compensation method, exposure method, and exposure equipment proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Any modifications to the structure, changes in proportions, or adjustments to the size, provided that the effects and objectives achieved by this invention are the same or similar, should still fall within the scope of the technical content disclosed in this invention. Specific design features of the invention disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific application and usage environment. Furthermore, in the embodiments described below, the same reference numerals are sometimes used across different figures to denote the same parts or parts having the same function, omitting repeated descriptions. In this specification, similar reference numerals and letters are used to denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures. Additionally, if the methods described herein comprise a series of steps, and the order of these steps presented herein is not necessarily the only possible order in which these steps can be performed, some described steps may be omitted and / or other steps not described herein may be added to the method.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The singular forms “a,” “one,” and “the” include plural objects. The term “or” is generally used to mean “and / or.” The term “several” is generally used to mean “at least one.” The term “at least two” is generally used to mean “two or more.” The term “multiple” is generally used to mean “at least two.”

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise expressly specified and limited, the terms "installed," "connected," "joined," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Moreover, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0060] To facilitate understanding, the specific structure of the exposure equipment will be explained first. Please refer to [link / reference needed]. Figure 1 This is a schematic diagram of the structure of an exposure device. For example... Figure 1 As shown, the exposure apparatus includes: an illumination system IL for adjusting the beam B to a suitable illumination beam; a mask stage RS for supporting a mask R and precisely moving the mask R to a working position, the mask R being used to adjust the beam B into the desired pattern; a workpiece stage WS for supporting a substrate W and precisely moving the substrate W to the working position; and a projection lens system PO for projecting the pattern of the beam B onto the substrate W.

[0061] The lighting system IL can include various optical elements, optomechanical components, and adjustment and control mechanisms to adjust and control the lighting beam through transmission, reflection, and blocking.

[0062] The mask stage RS is used to support and clamp the mask plate R. The clamping method can be mechanical, vacuum adsorption, etc. Depending on the needs of the exposure process, the mask stage RS can be fixed or movable. For structures that support multiple mask plates R, their pose can be controlled independently.

[0063] The mask R can adjust the beam into the desired pattern. The mask R can be transmissive, reflective, or arranged in an array.

[0064] The workpiece stage WS typically holds and fixes the substrate W using a vacuum adsorption method. The workpiece stage WS is usually movable, moving to the corresponding position to complete processes such as loading / unloading the substrate W, measurement, and exposure.

[0065] The substrate W typically needs to be coated with a photosensitive material to chemically react with a light beam and distinguish between patterns that need to be retained or removed. The substrate W can be composed of silicon wafers or compound materials.

[0066] The projection lens system PO may include various optical elements, optomechanical components, and adjustment and control mechanisms for transferring a pattern on a mask R onto a substrate W. The pattern on the mask R may differ from the pattern on the substrate W, and its size is typically reduced. The optical elements can project the pattern onto the substrate W through transmission or reflection, and the medium between the optical elements can be air, water, or other light-transmitting media.

[0067] The exposure equipment may have two or more workpiece stages WS to simultaneously complete multiple exposure processes; it may have multiple illumination systems IL, mask plates R, and projection lens systems PO, which are spliced ​​together to form a complete pattern.

[0068] The exposure equipment can have at least one of two working modes. One is the stepping mode, in which the mask R and the substrate W remain stationary during pattern projection, and the beam projects the pattern onto the substrate W in one go. The second is the scanning mode, in which the mask R and the substrate W are moved by the mask stage RS and the workpiece stage WS respectively during the pattern projection process. The pattern projected at each moment is a part of the complete pattern, and a complete scan forms a complete pattern.

[0069] When the projection lens is subjected to external impact, it may tilt, causing the projected pattern to shift, resulting in projection mismatch and subsequent overlay error.

[0070] The core idea of ​​this invention is to provide a position measuring device, a measuring method, a workpiece stage position compensation method, an exposure method, and an exposure equipment, which can measure the tilt angle of the objective lens, thereby compensating for the error caused by the tilt angle of the objective lens into the position of the workpiece stage, so as to reduce the impact of the objective lens position offset on the overlay accuracy of the exposure equipment.

[0071] To achieve the above-mentioned goals, this invention provides a position measuring device. Please refer to... Figure 2 and Figure 3 ,in, Figure 2 A schematic diagram of the overall structure of a position measuring device provided in one embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the measurement principle of a position measuring device provided in the first embodiment of the present invention. Figure 2 and Figure 3 As shown, the position measuring device includes a first reflecting mirror 111, a second reflecting mirror 112, a first interferometer reference axis 121, a second interferometer reference axis 122, and a data processing module 130. The first reflecting mirror 111 and the second reflecting mirror 112 are both mounted on the bottom of the objective lens 200, and their mounting heights at the bottom of the objective lens 200 are different. The first interferometer reference axis 121 is correspondingly arranged to the first reflecting mirror 111 and is configured to measure the first horizontal displacement of the objective lens 200. The second interferometer reference axis 122 is correspondingly arranged to the second reflecting mirror 112 and is configured to measure the second horizontal displacement of the objective lens 200. The data processing module 130 is configured to determine the yaw angle of the objective lens 200 based on the first and second horizontal displacements of the objective lens 200 and the height difference between the first and second interferometer reference axes 121 and 122.

[0072] Therefore, by using the position measuring device provided by the present invention, not only the horizontal displacement of the objective lens 200 can be measured, but also the tilt angle of the objective lens 200 can be measured. This allows for the compensation of errors caused by the translation of the objective lens 200 to the position of the workpiece stage WS, as well as errors caused by the tilt of the objective lens 200 to the position of the workpiece stage WS. This effectively reduces the impact of the positional offset of the objective lens 200 on the overlay accuracy of the exposure equipment, ensuring that the substrate W mounted on the workpiece stage WS can be exposed in the correct position, achieving the desired pattern fabrication, and improving the accuracy and reliability of the exposure process.

[0073] It should be noted that, as those skilled in the art will understand, the present invention does not limit the mounting angle of the first reflecting mirror 111 at the bottom of the objective lens 200, as long as the measurement light emitted from the first interferometer reference axis 121 can reach the first reflecting mirror 111 and return smoothly along its original path after being reflected by the first reflecting mirror 111. Similarly, the present invention does not limit the mounting angle of the second reflecting mirror 112 at the bottom of the objective lens 200, as long as the measurement light emitted from the second interferometer reference axis 122 can reach the second reflecting mirror 112 and return smoothly along its original path after being reflected by the second reflecting mirror 112. Furthermore, it should be noted that, as those skilled in the art will understand, the present invention does not limit the specific structure of the first interferometer reference axis 121 and the second interferometer reference axis 122. For details regarding the specific structure and measurement principle of the first interferometer reference axis 121 and the second interferometer reference axis 122, please refer to relevant content in the field of interferometers known to those skilled in the art, and will not be elaborated upon here.

[0074] In some exemplary embodiments, the tilt angle of the objective lens 200 is determined according to the following formula (1):

[0075]

[0076] Among them, such as Figure 3 As shown, ΔlensRy is the tilt angle of the objective lens 200, x LRA x is the first horizontal displacement of the objective lens 200. LRA ' is the second horizontal displacement of the objective lens 200, ΔH ref The height difference is between the first interferometer reference axis 121 and the second interferometer reference axis 122.

[0077] It should be noted that, as those skilled in the art will understand, the first horizontal displacement referred to herein refers to the magnitude of the first horizontal displacement (regardless of direction), and the second horizontal displacement refers to the magnitude of the second horizontal displacement (regardless of direction), i.e., x LRA and x LRA All are greater than or equal to 0. Furthermore, it should be noted that, as those skilled in the art will understand, the unit of the yaw angle ΔlensRy is rad.

[0078] Please continue to refer to this. Figure 2 and Figure 3 ,like Figure 2 and Figure 3As shown, in some exemplary embodiments, the first reflector 111 and the second reflector 112 are configured to be mounted on different sides of the objective lens 200, the first interferometer reference axis 121 is disposed on the first interferometer 151, and the second interferometer reference axis 122 is disposed on the second interferometer 152. The first interferometer 151 and the second interferometer 152 are configured to be separately disposed on different sides of the objective lens 200. Thus, by mounting the first reflector 111 and the second reflector 112 on different sides of the objective lens 200 (i.e., one of the first reflector 111 and the second reflector 112 is located on one side of the centerline of the objective lens 200, and the other of the first reflector 111 and the second reflector 112 is located on the other side of the centerline of the objective lens 200), and separately disposing the first interferometer reference axis 121 and the second interferometer reference axis 122 on different sides of the objective lens 200, not only can the bottom space of the objective lens 200 be fully utilized, but it also facilitates the first interferometer reference axis 111 to be mounted on different sides of the objective lens 200. The installation of the reflector 111 and the second reflector 112 ensures that the measurement light emitted from the first interferometer reference axis 121 can smoothly reach the first reflector 111 and be reflected back by the first reflector 111, and also ensures that the measurement light emitted from the second interferometer reference axis 122 can smoothly reach the second reflector 112 and be reflected back by the second reflector 112. This ensures that the first interferometer reference axis 121 can measure the first horizontal displacement of the objective lens 200, and the second interferometer reference axis 122 can smoothly measure the second horizontal displacement of the objective lens 200. Furthermore, by setting the first interferometer reference axis 121 and the second interferometer reference axis 122 on different interferometers, it is easier to achieve the corresponding setting of the first interferometer reference axis 121 and the first reflecting mirror 111 (the first interferometer reference axis 121 and the first reflecting mirror 111 are located on the same side of the objective lens 200), and the corresponding setting of the second interferometer reference axis 122 and the second reflecting mirror 112 (the second interferometer reference axis 122 and the second reflecting mirror 112 are located on the same side of the objective lens 200).

[0079] Please continue to refer to this. Figure 2 and Figure 3 ,like Figure 2 and Figure 3As shown, in some exemplary embodiments, the position measuring device further includes a first interferometer measuring axis 141, which is configured to measure the horizontal displacement of the workpiece stage WS (a reflecting mirror corresponding to the first interferometer measuring axis 141 is mounted on the side of the workpiece stage WS); the data processing module 130 is configured to determine the projection mismatch based on the yaw angle of the objective lens 200 and the height difference between the first interferometer measuring axis 141 and the first interferometer reference axis 121 and / or the second interferometer reference axis 122, and to determine the yaw displacement of the objective lens 200 projected onto the image plane based on the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens 200. Therefore, by setting a first interferometer measuring axis 141 for measuring the horizontal displacement of the workpiece stage WS, and determining the projection mismatch based on the yaw angle of the objective lens 200 and the height difference between the first interferometer measuring axis 141 and the first interferometer reference axis 121 and / or the second interferometer reference axis 122, it can be ensured that the yaw displacement of the optical axis of the objective lens 200 projected onto the image plane due to the yaw of the objective lens 200 can be calculated based on the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens 200.

[0080] It should be noted that, as those skilled in the art will understand, the position measuring device may also include an interferometer measuring axis for measuring the position information of the workpiece stage WS in degrees of freedom other than horizontal displacement, for example, such as Figure 2 The second interferometer measurement axis 142, the third interferometer measurement axis 143, and the fourth interferometer measurement axis 144 are shown. The workpiece stage WS is also equipped with other reflectors that correspond one-to-one with the second interferometer measurement axis 142, the third interferometer measurement axis 143, and the fourth interferometer measurement axis 144. It should be noted that, as those skilled in the art will understand, this invention does not limit the specific structure of each interferometer measurement axis (first interferometer measurement axis 141, second interferometer measurement axis 142, third interferometer measurement axis 143, fourth interferometer measurement axis 144, etc.). Regarding the specific structure and measurement principle of each interferometer measurement axis (first interferometer measurement axis 141, second interferometer measurement axis 142, third interferometer measurement axis 143, fourth interferometer measurement axis 144, etc.), please refer to relevant content in the field of interferometers known to those skilled in the art, and will not be elaborated further here.

[0081] In some exemplary embodiments, the projection mismatch is determined according to the following formula (2):

[0082]

[0083] Wherein, ΔS is the projection mismatch, ΔlensRy is the yaw angle of the objective lens 200, and ΔH... IFM1 The height difference ΔH between the first interferometer measurement axis 141 and the first interferometer reference axis 121 is given by the following formula: IFM2 The height difference between the first interferometer measurement axis 141 and the second interferometer reference axis 122 is used to measure the height difference between them.

[0084] Therefore, based on the tilt angle ΔlensRy of the objective lens 200 and the height difference ΔH between the first interferometer measurement axis 141 and the first interferometer reference axis 121... IFM1 The height difference ΔH between the first interferometer measuring axis 141 and the second interferometer reference axis 122 IFM2 The average value is used to determine the projection mismatch, which can effectively ensure the accuracy of the calculated projection mismatch. This can further reduce the impact of the objective lens position offset on the overlay accuracy of the exposure equipment and improve the accuracy and reliability of the exposure process.

[0085] Specifically, assuming the first horizontal displacement x of the objective lens 200 LRA The second horizontal displacement x of the objective lens 200 is 10nm to 50nm. LRA The height difference ΔH between the first interferometer reference axis 121 and the second interferometer reference axis 122 is 9nm to 30nm. ref The height difference ΔH between the reference axes 121 of the first interferometer is 20 mm. IFM1 The height difference ΔH between the first interferometer measuring axis 141 and the second interferometer reference axis 122 IFM2 The average value ΔH IFM Taking 25mm as an example, then:

[0086] The tilt angle of the objective lens 200 Projection mismatch ΔS=ΔlenRy·ΔH IFM =1.3nm~2.5nm.

[0087] Furthermore, the yaw displacement of the objective lens 200 projected onto the image plane can be determined according to the following formula (3):

[0088]

[0089] Where Δx is the yaw displacement of the objective lens 200 projected onto the image plane, x LRA x is the first horizontal displacement of the objective lens 200. LRA ' is the second horizontal displacement of the objective lens 200, and ΔS is the projection mismatch.

[0090] Therefore, based on the first horizontal displacement x of the objective lens 200 LRA The second horizontal displacement x of the objective lens 200 LRA The average value of ' and the yaw angle ΔlensRy based on objective lens 200, and the height difference ΔH between the first interferometer measurement axis 141 and the first interferometer reference axis 121. IFM1 The height difference ΔH between the first interferometer measuring axis 141 and the second interferometer reference axis 122 IFM2 The projection mismatch ΔS calculated from the average value is used to calculate the yaw displacement Δx projected by the objective lens 200 onto the image plane. This can effectively ensure the accuracy of the calculated yaw displacement Δx, thereby further reducing the impact of the objective lens 200 position offset on the overlay accuracy of the exposure equipment and improving the accuracy and reliability of the exposure process.

[0091] It should be noted that, as those skilled in the art will understand, in some other embodiments, the projection mismatch ΔS can also be determined according to the following formula (4):

[0092] ΔS=ΔlenRy·ΔH IFM1 (4)

[0093] Furthermore, the yaw displacement Δx projected by the objective lens 200 onto the image plane can be determined according to the following formula (5):

[0094] Δx=x LRA +ΔS (5)

[0095] In some other implementations, the projection mismatch ΔS can also be determined according to the following formula (6):

[0096] ΔS=ΔlenRy·ΔH IFM2 (6)

[0097] Furthermore, the yaw displacement Δx projected onto the image plane by the objective lens 200 can be determined according to the following formula (7):

[0098] Δx=x LRA '+ΔS (7)

[0099] Please continue to refer to this. Figure 2 and Figure 3 ,like Figure 2 and Figure 3As shown, in some exemplary embodiments, the first interferometer measurement axis 141 and the first interferometer reference axis 121 are integrated on the first interferometer 151. It should be noted that, as those skilled in the art will understand, in other exemplary embodiments, the first interferometer measurement axis 141 and the second interferometer reference axis 122 can also be integrated on the second interferometer 152. Therefore, by integrating the first interferometer measurement axis 141 with either the first interferometer reference axis 121 or the second interferometer reference axis 122 on the same interferometer, not only can the number of interferometers be reduced, lowering costs, but errors can also be reduced, further ensuring the accuracy of the acquired tilt angle of the objective lens 200.

[0100] Please continue to refer to this. Figure 4 This is a measurement principle diagram of a position measuring device provided in another embodiment of the present invention. Figure 4 As shown, the position measuring device provided in this embodiment differs from the position measuring device provided in the previous embodiment in that, in this embodiment, the first reflecting mirror 111 and the second reflecting mirror 112 are configured to be mounted on the same side of the objective lens 200, and the first interferometer reference axis 121 and the second interferometer reference axis 122 are integrated on the same interferometer. Therefore, by configuring the first reflecting mirror 111 and the second reflecting mirror 112 to be mounted on the same side of the objective lens 200, and integrating the first interferometer reference axis 121 and the second interferometer reference axis 122 on the same interferometer (first interferometer 151), not only can the number of interferometers be effectively reduced, further lowering costs, but also measurement errors can be further reduced.

[0101] Specifically, such as Figure 4 As shown, one of the first interferometer reference axis 121 and the second interferometer reference axis 122 is located directly above the other.

[0102] Please continue to refer to this. Figure 4 ,like Figure 4 As shown, in some exemplary embodiments, the first interferometer reference axis 121, the second interferometer reference axis 122, and the first interferometer measurement axis 141 are integrated on the same interferometer. Therefore, by integrating the first interferometer reference axis 121, the second interferometer reference axis 122, and the first interferometer measurement axis 141 on the same interferometer (first interferometer 151), not only can the number of interferometers be further reduced, effectively lowering costs, but errors can also be further reduced, thereby further ensuring the accuracy of the acquired yaw displacement of the objective lens 200.

[0103] It should be noted that, as those skilled in the art will understand, to avoid redundancy, this document only describes the differences between this embodiment and the previous embodiment. Regarding how the position measuring device provided in this embodiment determines the tilt angle of the objective lens 200 based on the first and second horizontal displacements of the objective lens 200 and the height difference between the first interferometer reference axis 121 and the second interferometer reference axis 122, the specific details can be found in the relevant content of the previous embodiment, and will not be repeated here. Furthermore, regarding how the position measuring device provided in this embodiment determines the tilt displacement projected onto the image plane of the objective lens 200 based on the tilt angle of the objective lens 200, the height difference between the first interferometer measuring axis 141 and the first interferometer reference axis 121 and / or the second interferometer reference axis 122, and the first and / or second horizontal displacements of the objective lens 200, the specific details can also be found in the relevant content of the previous embodiment, and will not be repeated here.

[0104] Based on the same inventive concept, this invention also provides a method for measuring the position of an objective lens, wherein a first reflecting mirror 111 and a second reflecting mirror 112 are mounted on the bottom of the objective lens 200, and the first reflecting mirror 111 and the second reflecting mirror 112 are mounted at different heights on the bottom of the objective lens 200. Please refer to... Figure 5 This is a flowchart illustrating a method for measuring the position of an objective lens according to an embodiment of the present invention. Figure 5 As shown, the objective lens position measurement method provided by the present invention includes the following steps:

[0105] Step S110: Measure the first horizontal displacement of the objective lens 200 through the optical path between the first interferometer reference axis 121 and the first reflecting mirror 111.

[0106] Step S120: Measure the second horizontal displacement of the objective lens 200 through the optical path between the second interferometer reference axis 122 and the second reflecting mirror 112.

[0107] Step S130: Determine the tilt angle of the objective lens 200 based on the first horizontal displacement and the second horizontal displacement of the objective lens 200 and the height difference between the first interferometer reference axis 121 and the second interferometer reference axis 122.

[0108] Therefore, by using the objective lens position measurement method provided by this invention, not only the horizontal displacement of the objective lens 200 can be measured, but also the tilt angle of the objective lens 200 can be measured. This allows for the compensation of errors caused by the translation of the objective lens 200 to the position of the workpiece stage WS, as well as errors caused by the tilt of the objective lens 200 to the position of the workpiece stage WS. Consequently, the impact of the objective lens 200 position offset on the overlay accuracy of the exposure equipment can be effectively reduced, ensuring that the substrate W mounted on the workpiece stage WS can be exposed in the correct position, achieving the desired pattern fabrication, and improving the accuracy and reliability of the exposure process.

[0109] In some exemplary embodiments, the objective lens position measurement method provided by the present invention further includes the following steps:

[0110] The projection mismatch is determined based on the yaw angle of the objective lens 200 and the height difference between the interferometer measuring axis and the first interferometer reference axis 121 and / or the second interferometer reference axis 122, wherein the interferometer measuring axis is used to measure the horizontal displacement of the workpiece stage WS;

[0111] The yaw displacement of the objective lens 200 projected onto the image plane is determined based on the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens 200.

[0112] Specifically, regarding how to determine the projection mismatch based on the yaw angle of the objective lens 200 and the height difference between the interferometer measurement axis and the first interferometer reference axis 121 and / or the second interferometer reference axis 122, and how to determine the yaw displacement of the objective lens 200 projected onto the image plane based on the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens 200, please refer to the relevant description above, which will not be repeated here.

[0113] Based on the same inventive concept, this invention also provides a workpiece stage WS position compensation method, please refer to [reference needed]. Figure 6 This is a flowchart illustrating a workpiece stage WS position compensation method provided in an embodiment of the present invention. Figure 6 As shown, the workpiece stage WS position compensation method provided by the present invention includes the following steps:

[0114] Step S210: Determine the yaw angle of the objective lens 200 using the position measuring device or the objective lens position measuring method described above.

[0115] Step S220: Determine the projection mismatch based on the yaw angle of the objective lens 200 and the height difference between the interferometer measuring axis and the first interferometer reference axis 121 and / or the second interferometer reference axis 122, wherein the interferometer measuring axis is used to measure the horizontal displacement of the workpiece stage WS.

[0116] Step S230: Determine the yaw displacement of the objective lens 200 projected onto the image plane based on the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens 200.

[0117] Step S240: Determine the correction position of the workpiece stage WS based on the yaw displacement of the objective lens 200 projected onto the image plane and the horizontal control position of the workpiece stage WS.

[0118] Therefore, by adopting the workpiece stage WS position compensation method provided by the present invention, not only can the error caused by the translation of the objective lens 200 be compensated to the position of the workpiece stage WS, but also the error caused by the sway of the objective lens 200 be compensated to the position of the workpiece stage WS. This can effectively reduce the impact of the position offset of the objective lens 200 on the overlay accuracy of the exposure equipment, ensure that the substrate W mounted on the workpiece stage WS can be exposed in the correct position, realize the fabrication of the required pattern, and improve the accuracy and reliability of the exposure process.

[0119] Specifically, the corrected position of the workpiece stage WS is determined according to the following formula (8):

[0120] x SPM =x enc -Δx (8)

[0121] Where, x SPM x is the corrected position of the workpiece stage WS. enc Δx is the horizontal control position of the workpiece stage WS, and Δx is the yaw displacement of the objective lens 200 projected onto the image plane.

[0122] Based on the same inventive concept, this invention also provides an exposure method, please refer to [reference needed]. Figure 7 This is a schematic flowchart of an exposure method provided in an embodiment of the present invention. Figure 7 As shown, the exposure method provided by the present invention includes the following steps:

[0123] Step S310: Use the workpiece stage WS position compensation method described above to determine the corrected position of the workpiece stage WS.

[0124] Step S320: Move the workpiece stage WS to the corrected position and expose the substrate W mounted on the workpiece stage WS.

[0125] Since the exposure method provided by this invention and the workpiece stage WS position compensation method provided by this invention belong to the same inventive concept, the exposure method provided by this invention has at least all the beneficial effects of the workpiece stage WS position compensation method provided by this invention. For details, please refer to the relevant description of the beneficial effects of the workpiece stage WS position compensation method provided by this invention above. Therefore, the beneficial effects of the exposure method provided by this invention will not be described in detail here.

[0126] Based on the same inventive concept, the present invention also provides an exposure apparatus, which includes the position measuring device described above. Since the exposure apparatus provided by the present invention includes the position measuring device provided by the present invention, the exposure apparatus provided by the present invention possesses at least all the beneficial effects of the position measuring device provided by the present invention. For details, please refer to the relevant descriptions of the beneficial effects of the position measuring device provided by the present invention above, which will not be repeated here. It should be noted that more information about the exposure apparatus provided by the present invention can be found in [reference needed]. Figure 1 The exposure equipment shown is for illustrative purposes only and will not be described in detail here.

[0127] Furthermore, taking the scanning mode of the exposure equipment as an example, during the online exposure process of the exposure equipment, 96 exposures are generally required. The exposure method described above can be used in each exposure field. Before the formal exposure, measurement is performed to determine the morphology and reference of the substrate W (silicon wafer), providing accurate control data for subsequent exposure.

[0128] During the exposure process, for each exposure field (taking the first field as an example, the horizontal control position of the workpiece stage WS is x). enc =-78mm) The horizontal displacement of the objective lens 200 is measured in real time using the first interferometer reference axis 121 and the second interferometer reference axis 122 (e.g., The yaw angle of the objective lens 200 is measured in real time using the first interferometer reference axis 121 and the second interferometer reference axis 122 (e.g., ΔlensRy = 50 nrad). According to formula (2) above, the projection mismatch (e.g., ΔS = 1.3 nm) is calculated. The objective lens 200 is an important component in the scanning exposure equipment for controlling light focusing and imaging quality. Measuring its horizontal displacement and projection mismatch can help determine the position and orientation of the objective lens 200, providing accurate reference data for subsequent position correction of the workpiece stage WS.

[0129] Immediately afterwards (within one servo cycle of 50µs), the actual position of the workpiece stage WS is measured using the first interferometer 151 and the second interferometer 152. The workpiece stage WS carries the target object (substrate W) to be processed on the exposure equipment. The accurate measurement of its position is crucial to ensuring the accuracy of the exposure position and pattern of the photoresist.

[0130] Next, the yaw displacement Δx of the optical axis of objective lens 200 projected onto the image plane is compensated to the horizontal control position (x) of the workpiece stage WS. enc =-78mm) to obtain the corrected position of the workpiece stage WS. By correcting the position of the workpiece stage WS, the accurate positioning and focusing of the light can be ensured, thereby improving the accuracy and stability of exposure.

[0131] Finally, move the workpiece stage WS to the correction position (the workpiece stage WS is moved to x). SPM = -78000011.3nm position), thereby ensuring that the substrate W mounted on the workpiece stage WS can be exposed in the correct position, thus ensuring the continuity and consistency of the pattern.

[0132] Repeat the above steps until all 96 exposure fields are completed. Through the real-time measurement and position correction described above, the exposure equipment can more accurately expose the photoresist on the substrate W, realize the desired pattern, and improve the accuracy and reliability of the exposure process.

[0133] In summary, compared with the prior art, the position measuring device, measuring method, workpiece stage WS position compensation method, exposure method, and exposure equipment provided by the present invention have the following beneficial effects:

[0134] This invention can measure not only the horizontal displacement of the objective lens 200, but also the tilt angle of the objective lens 200. Therefore, it can compensate for the errors caused by the translation of the objective lens 200 to the position of the workpiece stage WS, and also compensate for the errors caused by the tilt of the objective lens 200 to the position of the workpiece stage WS. This can effectively reduce the impact of the positional offset of the objective lens 200 on the overlay accuracy of the exposure equipment, ensure that the substrate W mounted on the workpiece stage WS can be exposed in the correct position, realize the fabrication of the required pattern, and improve the accuracy and reliability of the exposure process.

[0135] It should be noted that in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0136] It should also be noted that the above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure are within the protection scope of the present invention. Obviously, those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A position measuring device, characterized by The apparatus comprises a first mirror, a second mirror, a first interferometer reference axis, a second interferometer reference axis and a data processing module, the first mirror and the second mirror are configured to be installed at the bottom of the objective lens, and the installation heights of the first mirror and the second mirror at the bottom of the objective lens are different; The first interferometer reference axis is correspondingly arranged with the first mirror, and the first interferometer reference axis is configured to measure the first horizontal displacement of the objective lens; The second interferometer reference axis is correspondingly arranged with the second mirror, and the second interferometer reference axis is configured to measure the second horizontal displacement of the objective lens; The data processing module is configured to determine the yaw angle of the objective lens according to the first horizontal displacement and the second horizontal displacement of the objective lens and the height difference between the first interferometer reference axis and the second interferometer reference axis.

2. The position measuring device of claim 1, wherein, The yaw angle of the objective lens is determined according to the following formula: wherein, ΔlensRy is a yaw angle of the objective lens, x LRA is a first horizontal displacement of the objective lens, x LRA is a second horizontal displacement of the objective lens, ΔH ref is a height difference between the first interferometer reference axis and the second interferometer reference axis.

3. The position measuring device of claim 1, wherein, The first mirror and the second mirror are configured to be installed on the same side of the objective lens, and the first interferometer reference axis and the second interferometer reference axis are integrally arranged on the same interferometer.

4. The position measuring device of claim 1, wherein, The first mirror and the second mirror are configured to be installed on different sides of the objective lens, the first interferometer reference axis is arranged on a first interferometer, and the second interferometer reference axis is arranged on a second interferometer, and the first interferometer and the second interferometer are configured to be separately arranged on different sides of the objective lens.

5. The position measuring device of claim 1, wherein, The apparatus further comprises an interferometer measurement axis configured to measure the horizontal displacement of the worktable; and the data processing module is configured to determine the projection mismatch according to the yaw angle of the objective lens and the height difference between the interferometer measurement axis and the first interferometer reference axis and / or the second interferometer reference axis, and determine the yaw displacement of the objective lens on the image plane according to the projection mismatch and the first horizontal displacement and / or the second horizontal displacement of the objective lens.

6. The position measuring device of claim 5, wherein, The projection mismatch is determined according to the following formula: where ΔS is the projection mismatch, ΔlensRy is the decentre angle of the objective, ΔH IFM1 is the height difference between the interferometer measurement axis and the first interferometer reference axis, ΔH IFM2 is the height difference between the interferometer measurement axis and the second interferometer reference axis.

7. The position measuring device of claim 6, wherein, The yaw displacement of the objective lens on the image plane is determined according to the following formula: wherein Δx is the shift displacement of the objective lens projected on the image plane, x LRA is the first horizontal displacement of the objective lens, x LRA is the second horizontal displacement of the objective lens, and ΔS is the projection mismatch.

8. The position measuring device of claim 5, wherein, The interferometer measurement axis and the first interferometer reference axis and / or the second interferometer reference axis are integrally arranged on the same interferometer.

9. An objective lens position measurement method, characterized by, The bottom of the objective lens is provided with a first mirror and a second mirror, the installation heights of the first mirror and the second mirror at the bottom of the objective lens are different, and the measurement method comprises: The first horizontal displacement of the objective lens is measured through the optical path between the first interferometer reference axis and the first mirror; The second horizontal displacement of the objective lens is measured through the optical path between the second interferometer reference axis and the second mirror; The yaw angle of the objective lens is determined according to the first horizontal displacement and the second horizontal displacement of the objective lens and the height difference between the first interferometer reference axis and the second interferometer reference axis.

10. The objective position measurement method according to claim 9, wherein, The measurement method further comprises: The projection mismatch is determined according to the yaw angle of the objective lens and the height difference between the interferometer measurement axis and the first interferometer reference axis and / or the second interferometer reference axis, wherein the interferometer measurement axis is used to measure the horizontal displacement of the worktable; According to the projection mismatch amount and the first horizontal displacement and / or the second horizontal displacement of the objective lens, a yaw displacement of the objective lens projected on an image plane is determined.

11. A worktable position compensation method characterized by comprising: Comprising: Using the position measuring device according to any one of claims 1 to 8 or the objective lens position measuring method according to claim 9, a yaw angle of the objective lens is determined; According to the yaw angle of the objective lens and a height difference between an interferometer measuring axis and the first interferometer reference axis and / or the second interferometer reference axis, a projection mismatch amount is determined, wherein the interferometer measuring axis is used to measure a horizontal displacement of the workpiece table; According to the projection mismatch amount and the first horizontal displacement and / or the second horizontal displacement of the objective lens, a yaw displacement of the objective lens projected on an image plane is determined; According to the yaw displacement of the objective lens projected on the image plane and a horizontal control position of the workpiece table, a corrected position of the workpiece table is determined.

12. An exposure apparatus characterized by comprising: The exposure apparatus comprises the position measuring device according to any one of claims 1 to 8.

13. An exposure method characterized by, Comprising: Using the workpiece table position compensation method according to claim 11, a corrected position of the workpiece table is determined; Moving the workpiece table to the corrected position and exposing a substrate loaded on the workpiece table.

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