Exposure method and exposure device

Abstract

The present invention provides an exposure method and an exposure device. The exposure method includes: a mask and a substrate are synchronously moved in a first direction, and the substrate is exposed by a projection optical system so that the pattern on the mask is transferred to the substrate; and a moving action is performed, which moves the substrate in a second direction orthogonal to the first direction; the exposure method also includes: a dynamic alignment system is arranged opposite to a dynamic alignment mark arranged on a substrate or a substrate stage, and the dynamic alignment mark is arranged in a long strip shape and its length direction is the first direction; the dynamic alignment mark is detected by the dynamic alignment system at a preset detection interval during the movement of the substrate along the first direction; the dynamic alignment system makes the positions of the mask and the substrate match based on the detection results. The present invention can improve the positioning efficiency and positioning accuracy of the substrate stage under high-speed motion conditions, and can improve the yield.

Description

Technical Field

[0001] The present invention relates to the field of photolithography technology, and in particular to an exposure method and an exposure device. Background Art

[0002] Photolithography equipment is mainly used in the manufacture of integrated circuit chips or other micro devices. During the manufacturing process, the same device usually needs to undergo multiple photolithography exposures before it can be completed. During these exposure processes, the movement accuracy of the substrate stage is one of the key factors affecting the photolithography overlay accuracy. The alignment system is a core subsystem in semiconductor equipment. Taking the photolithography equipment as an example, the alignment accuracy of the alignment system often directly determines the overlay accuracy that the photolithography equipment can achieve.

[0003] In the related art, one of the step-by-step positioning and alignment methods is to locate the relative position relationship between the mask and the alignment mark configured on the substrate stage carrying the substrate at the guide position (often there are multiple different positions) during the scanning exposure process, and then align the mask with the substrate through the relative position relationship between the alignment marks. The defect of this method is that it causes the substrate stage to switch between multiple motion states such as acceleration, movement, deceleration and stop, which not only affects the stability of the substrate stage, but also affects the yield. Another method is to set up multiple groups of alignment mechanisms, and before the substrate stage moves to the specified position, a movable alignment mechanism is used to detect the exposure position, so as to achieve the exposure process without stopping the substrate stage. However, the defects of this method are that, first, it is not suitable for splicing exposure objective lenses, and second, a movable objective lens system and alignment system need to be set up.

[0004] It should be noted that the information disclosed in the background technology section of the invention is only intended to deepen the understanding of the general background technology of the invention, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide an exposure method and an exposure device to address one or more of the problems in the prior art of the step alignment positioning method under the high-speed movement condition of the substrate stage, namely, affecting the stability and efficiency of the substrate stage, and causing motion blur / smear in machine vision positioning. The present invention can improve the positioning efficiency and positioning accuracy of the substrate stage under the high-speed movement condition without affecting the stability of the substrate stage, thereby improving the productivity.

[0006] To achieve the above object, the present invention is implemented by the following technical scheme: an exposure method, which causes a mask and a substrate to move synchronously in a first direction, while performing exposure on the substrate through a projection optical system, so that a pattern on the mask is transferred to the substrate; and a moving action, which causes the substrate to move in a second direction orthogonal to the first direction; the exposure method also includes:

[0007] A dynamic alignment system, wherein the dynamic alignment system is arranged opposite to a dynamic alignment mark arranged on the substrate or the substrate stage, the dynamic alignment mark is arranged in a long strip shape, and the length direction of the dynamic alignment mark is the first direction;

[0008] By means of the dynamic alignment system, the dynamic alignment mark is detected at a preset detection interval during the movement of the substrate along the first direction;

[0009] The dynamic alignment system makes the positions of the mask and the substrate match based on the detection result.

[0010] Optionally, the detecting the dynamic alignment mark at a preset detection interval during the movement of the substrate along the first direction by the dynamic alignment system includes:

[0011] When the substrate stage is located at an initial position, obtaining first position information of the dynamic alignment mark in a coordinate system where the substrate is located;

[0012] During the movement of the substrate, a characteristic image of the dynamic alignment mark is collected according to the preset detection interval duration; and second position information of the characteristic image in the coordinate system where the dynamic alignment system is located is obtained in real time;

[0013] According to the coordinate conversion relationship between the coordinate system of the substrate and the coordinate system of the dynamic alignment system, the second position information is converted to the coordinate system of the substrate to obtain the third position information, and the detection result is obtained according to the initial position of the substrate, the third position information and the first position information.

[0014] Optionally, acquiring in real time the second position information of the characteristic image in the coordinate system where the dynamic alignment system is located includes:

[0015] Processing the feature image using an image edge extraction method to obtain an edge image;

[0016] Acquire second position information of the edge image in the coordinate system where the dynamic alignment system is located.

[0017] Optionally, the dynamic alignment mark includes a single linear mark; the length of the single linear mark is greater than or equal to the product of the preset detection interval time and the movement speed of the substrate.

[0018] Optionally, the dynamic alignment system includes an image acquisition device, the dynamic alignment mark includes at least two first sub-linear marks spaced apart along the movement direction of the substrate, and the maximum distance between the first sub-linear marks is smaller than the maximum field of view of the image acquisition device on the object side along the movement direction of the substrate.

[0019] Optionally, the line widths of the first sub-linear marks are the same.

[0020] Optionally, the line widths of the first sub-linear marks are different, and the real-time acquisition of the second position information of the characteristic image in the coordinate system where the dynamic alignment system is located includes:

[0021] Obtaining second position information corresponding to the first sub-linear mark according to a first calibration coefficient of line width variation and movement speed of the substrate, a second calibration coefficient of a relationship between the line width of the first sub-linear mark and its position, and the line width of the first sub-linear mark;

[0022] The line width change is the absolute value of the difference between the line width of the first sub-linear mark and the line width of another adjacent first sub-linear mark in the characteristic image.

[0023] Optionally, the strip feature mark includes at least two linear combination marks spaced apart along the direction of movement of the substrate; each of the linear combination marks includes at least two second sub-linear marks spaced apart, and the extension direction of the second sub-linear marks is parallel to the direction of movement of the substrate; different linear combination marks have different distributions of the second sub-linear marks, the intervals between the second sub-linear marks, the number of the second sub-linear marks and / or the line width of at least one second sub-line mark.

[0024] Optionally, the coordinate conversion relationship between the coordinate system where the substrate is located and the coordinate system where the dynamic alignment system is located is calibrated when the substrate is in a stationary state.

[0025] Optionally, for each of the first sub-linear marks, the exposure method further comprises calibrating the line width of the first sub-linear mark by the following steps:

[0026] In the process of correcting the first rotation angle between the first sub-linear mark and the moving direction of the substrate to be zero, acquiring a plurality of magnification test data of the image acquisition device;

[0027] When the first rotation angle is zero and the substrate moves at a preset speed, the sub-linear images of the first sub-linear mark are collected according to different first calibration sampling intervals, and multiple acquisition delay times of the image acquisition device are calibrated during the acquisition process;

[0028] Correcting the magnification error of the image acquisition device according to the image acquisition delay time;

[0029] When the first rotation angle is a different non-zero value and the substrate moves at a preset speed, the sub-linear image of the first sub-linear mark is acquired according to different second calibration sampling intervals, and the relationship between the first rotation angle and the line width of the first sub-linear mark is calibrated during the acquisition process;

[0030] Correcting the magnification coefficient of the image acquisition device according to the plurality of magnification test data and the magnification error;

[0031] Correcting a line width variation error of the first sub-linear mark according to a relationship between the first rotation angle and the line width of the first sub-linear mark and the magnification error;

[0032] The line width of the first sub-linear mark is calibrated according to the corrected magnification factor and the corrected line width variation error.

[0033] In order to achieve the above object, the present invention further provides an exposure device, comprising a mask stage for holding a mask, a substrate stage for holding a substrate, and a projection optical system, wherein the mask stage and the substrate stage are synchronously moved in a first direction while the substrate is exposed so that a pattern on the mask is transferred to the substrate;

[0034] The substrate stage is movable along a second direction orthogonal to the first direction;

[0035] The exposure device further comprises:

[0036] A dynamic alignment mark is arranged on the substrate or the substrate stage, the dynamic alignment mark is arranged in a long strip shape, and the length direction of the dynamic alignment mark is the first direction;

[0037] a dynamic alignment system, the dynamic alignment system being arranged opposite to the dynamic alignment mark and detecting the dynamic alignment mark at a preset detection interval during the movement of the substrate along the first direction;

[0038] The dynamic alignment system makes the positions of the mask and the substrate match based on the detection result.

[0039] Optionally, the dynamic alignment mark is one of a single linear mark, at least two first sub-linear marks spaced apart along the direction of movement of the substrate, and at least two linear combination marks spaced apart along the direction of movement of the substrate, the linear combination mark includes at least two second sub-linear marks spaced apart, and the extension direction of the second sub-linear marks is parallel to the direction of movement of the substrate; the layout of the second sub-linear marks of the linear combination marks at different positions, the intervals between the second sub-linear marks, the number of the second sub-linear marks and / or the line width of at least one second sub-line mark are different.

[0040] Compared with the prior art, the exposure method and exposure device provided by the present invention have the following advantages:

[0041] The exposure method provided by the present invention has a dynamic alignment system with a sensor (such as an image acquisition device), fast motion state update, and high automation rate. Compared with the static alignment measurement method in the prior art, the exposure method provided by the present invention can synchronously perform dynamic measurement during the scanning exposure process without frequently stopping the substrate stage for static mark alignment during the exposure process, avoiding frequent acceleration and deceleration of the substrate stage, thereby improving the productivity of the lithography equipment. In addition, the solution provided by the present invention can also be used in parallel with the static alignment system in the prior art, so that the lithography equipment has both static and dynamic alignment modes.

[0042] Since the exposure device provided by the present invention belongs to the same inventive concept as the exposure method provided by the present invention, the exposure device provided by the present invention at least has all the advantages of the exposure method provided by the present invention. For details, please refer to the description related to the exposure method above, and no further details will be given here. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic structural diagram of an exposure device provided in one embodiment of the present invention;

[0044] Figure 2 for Figure 1 A top view of a first exemplary embodiment in which both the dynamic alignment mark and the static alignment mark of the exposure device are arranged on the substrate stage;

[0045] Figure 3 A schematic diagram of a dynamic alignment mark of a second exemplary embodiment of an exposure device provided by the present invention;

[0046] Figure 4 A schematic diagram of a dynamic alignment mark of a third exemplary embodiment of an exposure device provided by the present invention;

[0047] Figure 5A schematic diagram of a dynamic alignment mark of a fourth exemplary embodiment of an exposure device provided by the present invention;

[0048] Figure 6 A schematic flow chart of an exposure method provided by another embodiment of the present invention;

[0049] Figure 7 A schematic diagram of the corresponding relationship between a single linear mark and a collection interval of an image acquisition device when the exposure method provided by the present invention is applied to a first exemplary implementation of a dynamic alignment mark of an exposure device;

[0050] Figure 8 A schematic diagram of the corresponding relationship between the distance between two adjacent first sub-linear marks and the acquisition interval of the image acquisition device when the exposure method provided by the present invention is applied to the second exemplary implementation of the dynamic alignment mark of the exposure device;

[0051] Fig. 9 A schematic diagram of line width variation between two adjacent first sub-linear marks when the exposure method provided by the present invention is applied to a third exemplary implementation of a dynamic alignment mark of an exposure device;

[0052] Fig.10 An overall flow chart of calibrating the line width of the first sub-linear mark in an exposure method provided by one embodiment of the present invention;

[0053] Fig.11 for Fig.10 A specific example diagram of calibrating the line width of the first sub-linear mark;

[0054] Fig.12a Schematic diagram of image acquisition when there is Rv=0 in the moving direction of the dynamic alignment mark and the substrate stage;

[0055] Figure 12b It is a rotation diagram in which the camera and the substrate stage have Rc≠Rv in their moving directions;

[0056] Fig.12c It is a schematic diagram of dynamic alignment mark smear imaging;

[0057] The reference numerals are as follows:

[0058] Mask-110, substrate-120, substrate pattern area-111;

[0059] Mask stage 210, substrate stage 220, projection optical system 230, motion control system 231, optical system 232;

[0060] Dynamic alignment system-310, dynamic alignment mark-320, first sub-linear mark-321, second sub-linear mark-322, static alignment mark-330. DETAILED DESCRIPTION

[0061] The following is a further detailed description of the exposure method and exposure device proposed in the present invention in conjunction with the accompanying drawings. According to the following description, the advantages and features of the present invention will be more clear. It should be noted that the drawings are in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Any modification of the structure, change in the proportional relationship or adjustment of the size, under the same or similar conditions as the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. The specific design features of the present invention disclosed herein include, for example, specific dimensions, directions, positions and shapes, which will be determined in part by the specific environment to be applied and used. And, in the embodiments described below, sometimes the same figure mark is used in common between different drawings to represent the same part or part with the same function, and its repeated description is omitted. In this specification, similar reference numerals and letters are used to refer to similar items, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures. In addition, if the method described herein includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method.

[0062] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements. The singular forms "a", "an" and "the" include plural objects, the term "or" is generally used in a sense including "and / or", the term "several" is generally used in a sense including "at least one", and the term "at least two" is generally used in a sense including "two or more". In addition, the terms "first", "second" and "third" are used for descriptive purposes only and are not to be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features.

[0063] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “line width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0064] In order to facilitate the understanding of the present invention, the exposure device provided by the present invention is first described in detail herein, and then the exposure method provided by the present invention is described in detail. It should be noted that those skilled in the art should be able to understand that, as a preference, the exposure device provided by the present invention can be exposed using the exposure method provided by the present invention to improve the yield of the lithography equipment. Correspondingly, the exposure method provided by the present invention can be applied to the exposure device provided by the present invention to improve the yield of the lithography equipment.

[0065] Specifically, see Figure 1 and Figure 2 ,in, Figure 1 A structural block diagram of an exposure device provided in one embodiment of the present invention, Figure 2 for Figure 1A top view of a specific example in which the dynamic alignment mark and the static alignment mark of the exposure device are both arranged on the substrate. Figure 1 and Figure 2 It can be seen that the exposure device provided in this embodiment includes a mask stage 210 for holding a mask 110, a substrate stage 220 for holding a substrate 120, and a projection optical system 230. Specifically, the projection optical system 230 may further include a motion control system 231 and an optical system 232. The motion control system 231 (the black thick line in the figure indicates the connection relationship with the mask stage 110 and the substrate stage 220) moves the mask stage 210 and the substrate stage 220 in a first direction ( Figure 1 The optical system 232 performs exposure on the substrate 120 so that the pattern on the mask 110 is transferred to the substrate 120; the substrate stage 220 can move synchronously in a second direction ( Figure 1 The exposure device further includes: a dynamic alignment mark 320 disposed on the substrate 120 or the substrate stage 220, the dynamic alignment mark 320 being arranged in a long strip shape, the length direction of the dynamic alignment mark 320 being the first direction; a dynamic alignment system 310, the dynamic alignment system 310 being arranged opposite to the dynamic alignment mark 320 ( Figure 1 The dynamic alignment system 310 is only schematically described), and the dynamic alignment mark 320 is detected at a preset detection interval during the movement of the substrate 120 along the first direction; the dynamic alignment system 310 makes the positions of the mask 110 and the substrate 120 match based on the detection results.

[0066] It can be seen that the exposure device provided in this embodiment, the dynamic alignment system 310 has the advantages of sensors (not shown in the figure, such as image acquisition devices), fast motion state update, and high automation rate. Compared with the static alignment measurement method in the prior art, the exposure device provided in this embodiment can perform dynamic measurement synchronously during the scanning exposure process without frequently stopping the substrate stage 220 for static mark alignment during the exposure process, avoiding frequent acceleration and deceleration of the substrate stage 220, thereby improving the productivity of the lithography equipment. In addition, the solution provided in this embodiment can also be used in parallel with the static alignment system in the prior art, so that the lithography equipment has both static and dynamic alignment modes.

[0067] It should be noted that, since the basic principle of the dynamic alignment system 310 of the exposure device provided in this embodiment "detects the dynamic alignment mark 320 at a preset detection interval during the movement of the substrate 120 along the first direction; and based on the detection result, the positions of the mask 110 and the substrate 120 are matched" is similar to the basic principle of the exposure method provided in the following embodiment, in order to avoid redundancy, it will not be described in detail here. For a more detailed description of this part, please refer to the corresponding part of the adaptive understanding in the exposure method below. In addition, as mentioned above, the dynamic alignment mark 320 can be set on the substrate 120 or on the substrate stage 220. The present invention does not limit this. For the convenience of description and understanding, unless otherwise specified, the following description will be based on the example of the dynamic alignment mark 320 being set on the substrate stage 220. Those skilled in the art should be able to understand that the movement of the substrate stage 220 will drive the synchronous movement of the substrate 120 placed thereon (that is, the substrate 120 moves along with the substrate stage 220, and it can be understood that the substrate 120 and the substrate stage 220 are relatively stationary). Therefore, by detecting the position of the dynamic alignment mark 320 set on the substrate stage 220, the position of the substrate 120 is detected, thereby laying a good foundation for matching the positions of the mask 110 and the substrate 120.

[0068] The dynamic alignment mark 320 of the exposure device provided by the first exemplary embodiment of the present invention is shown in FIG. Figure 2 ,from Figure 2 It can be seen that in this exemplary embodiment, the dynamic alignment mark 320 is a single linear mark. For more details on how the dynamic alignment system 310 detects the dynamic alignment mark 320 and how to make the positions of the mask 110 and the substrate 120 coincide based on the detection results, please refer to the partial adaptability understanding corresponding to the exposure method provided in the following embodiment, and no further elaboration will be given here.

[0069] The dynamic alignment mark 320 of the exposure device provided by the second exemplary embodiment of the present invention is shown in FIG. Figure 3 , Figure 3 A schematic diagram of a dynamic alignment mark of a second exemplary embodiment of an exposure device provided by the present invention is schematically provided. Figure 3 It can be seen that in the second exemplary embodiment, the dynamic alignment mark 320 is at least two first sub-linear marks 321 spaced apart along the moving direction of the substrate 120 .

[0070] The third exemplary embodiment of the present invention provides a dynamic alignment mark 320 of an exposure device, see Figure 4 , Figure 4A schematic diagram of a dynamic alignment mark of a third exemplary embodiment of the exposure device provided by the present invention is schematically provided. Figure 3 and Figure 4 It is easy to see that: similar to the second exemplary embodiment, the dynamic alignment mark 320 in the third exemplary embodiment is also at least two first sub-linear marks 321 spaced apart along the movement direction of the substrate 120, but the dynamic alignment mark 320 of the exposure device provided in the third exemplary embodiment is different from the dynamic alignment mark 320 of the exposure device provided in the second exemplary embodiment in that the line widths of the first sub-linear marks 321 are the same in the second exemplary embodiment, while in the third exemplary embodiment, the line widths of the first sub-linear marks 321 are different.

[0071] The fourth exemplary embodiment of the present invention provides a dynamic alignment mark 320 of an exposure device, see Figure 5 , Figure 5 A schematic diagram of a dynamic alignment mark of a fourth exemplary embodiment of the exposure device provided by the present invention is schematically provided. Figure 5 It can be seen that in the fourth exemplary embodiment, the dynamic alignment mark 320 is at least two linear combination marks spaced apart along the moving direction of the substrate 120. Specifically, the linear combination mark includes at least two second sub-linear marks 322 spaced apart, and the extending direction of the second sub-linear marks 322 is parallel to the moving direction of the substrate 120. The layout of the second sub-linear marks 322, the spacing between the second sub-linear marks 322, the number of the second sub-linear marks 322 and / or the line width of at least one second sub-linear mark of the linear combination marks at different positions are different. For example, as Figure 5 Three dynamic alignment marks 320 are shown, the leftmost ( Figure 5 The dynamic alignment mark 320 (in the direction shown) includes five second sub-linear marks 322, and along Figure 5 From left to right in the direction shown, the intervals between the five second sub-linear marks 322 are all the first distance, and the line widths of the five second sub-linear marks 322 gradually increase; Figure 5 The dynamic alignment mark 320 (in the direction shown) also includes five second sub-linear marks 322, and along Figure 5 From left to right in the direction shown, the intervals between the five second sub-linear marks 322 are all the second distance, and the line widths of the five second sub-linear marks 322 first gradually decrease and then gradually increase; Figure 5 The dynamic alignment mark 320 (in the direction shown) also includes five second sub-linear marks 322, along Figure 5From left to right in the direction shown, the intervals between the five second sub-linear marks 322 are all the third distance, and the line widths of the five second sub-linear marks 322 gradually decrease. The first distance is smaller than the second distance, and the second distance is smaller than the third distance.

[0072] It should be noted that those skilled in the art should be able to understand that the above description of the dynamic alignment mark 320 of the exposure device provided by the present invention is only an exemplary description, and not a limitation of the present invention. For example, in other embodiments, the dynamic alignment mark 320 may also be a combination of any two or more dynamic alignment marks 320 of the above-mentioned first embodiment, second embodiment, third embodiment and fourth embodiment, that is, the dynamic alignment mark 320 may be either a continuous long strip mark or a combination of discrete short graphic marks, which will not be described one by one herein.

[0073] Next, the exposure method provided by the present invention is described in detail as follows:

[0074] Another embodiment of the present invention provides an exposure method. The exposure method provided by this embodiment includes: while the mask 110 and the substrate 120 are synchronously moved in a first direction, the substrate 120 is exposed through the projection optical system 230, so that the pattern on the mask 110 is transferred to the substrate 120; and a moving action is performed, which moves the substrate 120 in a second direction orthogonal to the first direction. At the same time, please refer to Figure 6 , Figure 6 A schematic flow chart of the exposure method provided in this embodiment, from Figure 6 It can be seen that the exposure method provided in this embodiment further includes:

[0075] S100: A dynamic alignment system 310 is arranged opposite to a dynamic alignment mark 320 arranged on the substrate 120 or the substrate stage 220, the dynamic alignment mark 320 is arranged in a long strip shape, and the length direction of the dynamic alignment mark 320 is the first direction;

[0076] S200: Using the dynamic alignment system 310, the dynamic alignment mark 320 is detected at a preset detection interval during the movement of the substrate 120 along the first direction;

[0077] S300: The dynamic alignment system 310 makes the positions of the mask 110 and the substrate 120 match based on the detection result.

[0078] Therefore, the exposure device provided in this embodiment, the dynamic alignment system 310 has the advantages of a sensor (not shown in the figure, such as an image acquisition device), fast motion state update, and high automation rate. Compared with the static alignment measurement method in the prior art, the exposure device provided in this embodiment can perform dynamic measurement synchronously during the scanning exposure process without frequently stopping the substrate stage 220 for static mark alignment during the exposure process, avoiding frequent acceleration and deceleration of the substrate stage 220, thereby improving the yield of the lithography equipment. In addition, the solution provided in this embodiment can also be used in parallel with the static alignment system in the prior art, so that the lithography equipment has both static and dynamic alignment modes. Specifically, for more detailed information on how to achieve static alignment of the lithography equipment through the static alignment system and the static alignment mark 330, please refer to the relevant technology known to those skilled in the art. Due to space limitations, it will not be described in detail here.

[0079] Preferably, in some exemplary embodiments, in step S200, the dynamic alignment mark 320 is detected by the dynamic alignment system 310 at a preset detection interval during the movement of the substrate 120 along the first direction, specifically including:

[0080] S210: When the substrate stage 220 is located at an initial position, obtaining first position information of the dynamic alignment mark 320 in the coordinate system where the substrate 120 is located;

[0081] S220: During the movement of the substrate 120, a characteristic image of the dynamic alignment mark 320 is collected according to the preset detection interval duration; and second position information of the characteristic image in the coordinate system where the dynamic alignment system 310 is located is obtained in real time;

[0082] S230: According to the coordinate conversion relationship between the coordinate system of the substrate 120 and the coordinate system of the dynamic alignment system 310, the second position information is converted to the coordinate system of the substrate 120 to obtain the third position information, and the detection result is obtained according to the initial position of the substrate 120, the third position information and the first position information.

[0083] The exposure method provided in the present embodiment obtains the first position information of the dynamic alignment mark 320 in the coordinate system where the substrate 120 is located when the substrate stage 220 is located at the initial position; and during the movement of the substrate 120, collects the characteristic image of the dynamic alignment mark 320 according to the preset detection interval duration; and obtains the second position information of the characteristic image in the coordinate system where the dynamic alignment system 310 is located in real time; and according to the coordinate conversion relationship between the coordinate system where the substrate 120 is located and the coordinate system where the dynamic alignment system 310 is located, converts the second position information to the coordinate system where the substrate 120 is located to obtain the third position information, and obtains the detection result according to the initial position of the substrate 120, the third position information and the first position information. In this way, the position information of the dynamic alignment mark 320 in the coordinate system of the substrate 120 can be obtained in real time, so as to determine the real-time position information of the substrate 120 in real time; moreover, the whole process of obtaining the detection result is achieved by the dynamic alignment system 310 collecting the characteristic image of the dynamic alignment mark 320 in real time. Therefore, during the whole exposure process, there is no need to frequently stop the substrate stage 220 for static mark alignment, thereby avoiding frequent acceleration and deceleration movements of the substrate stage 220, which can significantly improve the productivity of the lithography equipment.

[0084] Preferably, in one exemplary embodiment, in step S230, the coordinate conversion relationship between the coordinate system of the substrate 120 and the coordinate system of the dynamic alignment system 310 is calibrated when the substrate 120 is in a stationary state. Such a configuration can further improve the measurement accuracy.

[0085] In addition, it is particularly important to emphasize once again that, as mentioned above, since the substrate 120 and the substrate stage 220 are relatively stationary, the position information of the dynamic alignment mark 320 in the coordinate system of the substrate 120 is equivalent to the position information of the dynamic alignment mark 320 in the coordinate system of the substrate stage 220.

[0086] Preferably, in some exemplary implementations, correspondingly, step S220 acquires the second position information of the feature image in the coordinate system where the dynamic alignment system 310 is located in real time, specifically including:

[0087] S22A1: Processing the feature image using an image edge extraction method to obtain an edge image;

[0088] S22A2: Obtain second position information of the edge image in the coordinate system where the dynamic alignment system 310 is located.

[0089] Therefore, the exposure method provided in this embodiment processes the feature image by adopting an image edge extraction method to obtain an edge image, and then obtains the second position information of the edge image in the coordinate system where the dynamic alignment system 310 is located as the second position information of the feature image in the coordinate system where the dynamic alignment system 310 is located. This can ensure that the generation of ghosting when collecting the feature image does not affect the image edge extraction accuracy, thereby reducing the impact of ghosting on positioning accuracy and further improving positioning efficiency.

[0090] Specifically, the exposure method provided by the present invention does not limit the image edge extraction method, and the image edge extraction method can use either the edge operator of the first-order derivative or the edge operator of the second-order derivative, or a foreground operator other than the edge operator of the first-order derivative and the edge operator of the second-order derivative. Exemplarily, the edge operators mentioned above include but are not limited to Roberts operator, Sobel operator, Prewitt operator, Laplacian operator, and Canny edge detection, etc. For more detailed information about the image edge extraction method, please refer to the relevant technology known to those skilled in the art, which will not be described in detail here.

[0091] See also Figure 7 , which schematically shows a first exemplary implementation of the exposure method provided by the present invention applied to a dynamic alignment mark of an exposure device (that is, when the dynamic alignment mark is Figure 5 Schematic diagram of the corresponding relationship between the single linear mark and the acquisition interval of the image acquisition device when the dynamic alignment mark is shown. Figure 7 It can be seen that the dynamic alignment mark 320 includes a single linear mark; the length of the single linear mark is greater than or equal to the product of the preset detection interval time length and the movement speed of the substrate 120. Therefore, by setting the length of the single linear mark to be greater than or equal to the product of the preset detection interval time length and the movement speed of the substrate 120, the detection accuracy can be guaranteed when the substrate stage 220 moves at a uniform and high speed without increasing the cost.

[0092] Specifically, in order to facilitate understanding of the present invention, the basic principle of setting the length of the single linear mark to be greater than or equal to the product of the preset detection interval time and the movement speed of the substrate 120 is roughly described as follows: Taking the use of a camera (usually an industrial camera) to capture the characteristic image of the dynamic alignment mark 320 at high speed as an example, the minimum exposure time of the camera can determine the movement speed of the substrate stage 220. For example, when the movement speed of the substrate stage 220 is 1m / s and the measurement accuracy is 0.1μm / pixel, the smear caused by the movement of the dynamic alignment mark 320 must be less than the measurement accuracy of 0.1μm, and correspondingly, the exposure time of the camera must be less than 0.1μm. The extreme exposure time requirement also requires higher light energy. In turn, the performance of the industrial camera and lighting will affect the upper limit of the speed of the substrate stage 220, which is bound to require a higher cost. Therefore, by setting the length of the single linear mark to be greater than or equal to the product of the preset detection interval time and the movement speed of the substrate 120, the mutual constraints between the measurement accuracy, the camera performance and the movement speed of the substrate stage 220 are well balanced. More specifically, see Figure 7 , Figure 7 In the equation (1), L is the minimum length of the single linear marker, and the two solid boxes marked as CAM are the acquisition positions of the feature image. The length of the single linear marker can be expressed by the following formula (1):

[0093] L>t×v (1)

[0094] In formula (1), L is the length of the single linear mark along the moving direction of the substrate stage 220, t is the preset detection interval time, and v is the relative moving speed between the substrate stage 220 and the camera.

[0095] Preferably, in some exemplary embodiments, the dynamic alignment system 310 includes an image acquisition device (not shown in the figure). Specifically, in the second exemplary embodiment, please continue to refer to Figure 3 as well as Figure 8 ,in, Figure 8 This is a schematic diagram of the corresponding relationship between the distance between two adjacent first sub-linear marks 321 and the acquisition interval of the image acquisition device when the exposure method provided by the present invention is applied to the second exemplary implementation of the dynamic alignment mark of the exposure device. Figure 3 and Figure 8It can be seen that the dynamic alignment mark 320 includes at least two first sub-linear marks 321 spaced apart along the moving direction of the substrate 120, and the maximum distance between the first sub-linear marks 321 is smaller than the maximum field of view of the image acquisition device on the object side along the moving direction of the substrate 120. Therefore, by setting the maximum distance between the first sub-linear marks 321 to be smaller than the maximum field of view of the image acquisition device on the object side along the moving direction of the substrate 120, the detection accuracy can be ensured when the substrate stage 220 moves at a uniform and high speed without increasing the cost.

[0096] Specifically, regarding the principle of setting the maximum distance between the first sub-linear marks 321 to be smaller than the maximum field of view of the object side of the image acquisition device along the movement direction of the substrate 120, please refer to the above-mentioned description of the basic principle of setting the length of the single linear mark to be greater than or equal to the product of the preset detection interval duration and the movement speed of the substrate 120, which will not be repeated here.

[0097] More specifically, see Figure 8 , Figure 8 In the formula (2), S is the maximum distance between the first sub-linear markers 321, M is the maximum field of view of the image acquisition device in the object direction along the moving direction of the substrate 120, and the two solid boxes marked as CAM are the acquisition positions of the feature images. The maximum distance S between the first sub-linear markers 321 can be expressed by the following formula (2):

[0098] S<M (2)

[0099] In formula (2), S is the maximum distance between the first sub-linear marks 321, and M is the maximum field of view of the image acquisition device in the object side along the moving direction of the substrate 120.

[0100] It should be noted that, as can be understood by those skilled in the art, in actual application, completely eliminating imaging smear has a very low cost-effectiveness for the overall system performance and is even unattainable. Therefore, from the perspective of actual application, as a preferred method, the image edge extraction algorithm can be further used to ensure that the generation of smear does not affect the edge extraction accuracy of the image, thereby further reducing the impact of smear on positioning accuracy and further improving positioning efficiency.

[0101] More specifically, if Figure 3 and Figure 8 As shown, in the second exemplary embodiment, the line widths of the first sub-linear marks 321 are the same. In this way, in the exposure method provided by the present invention, the dynamic alignment mark 320 uses the first sub-linear marks 321 with the same line width, which does not increase too much calculation during feature image processing, thereby further improving the productivity of the lithography equipment.

[0102] Preferably, in the third exemplary embodiment, the line widths of the first sub-linear marks are different. Correspondingly, step S220 acquires the second position information of the feature image in the coordinate system of the dynamic alignment system in real time, including:

[0103] S22B1: Obtain second position information corresponding to the first sub-linear mark based on a first calibration coefficient of the line width change and the movement speed of the substrate, a second calibration coefficient of the relationship between the line width of the first sub-linear mark and its position, and the line width of the first sub-linear mark; wherein the line width change is the absolute value of the difference between the line width of the first sub-linear mark and the line width of another adjacent first sub-linear mark in the characteristic image.

[0104] Specifically, see Fig. 9 , Fig. 9 A schematic diagram of line width variation between two adjacent first sub-linear marks when the exposure method provided by the present invention is applied to a third exemplary implementation of a dynamic alignment mark of an exposure device. Fig. 9 , dL is the left side ( Fig. 9 The line width of the first sub-linear marker on the right side ( Fig. 9 The second position information of the first sub-linear mark on the right side can be calculated by the following formula (3):

[0105] K×|dL-dR|+b×dR(3)

[0106] In formula (3), |dL-dR| is the line width variation, that is, the absolute value of the difference between the line width dR of the first sub-linear mark and the line width dL of another adjacent first sub-linear mark in the characteristic image; k is a first calibration coefficient of the line width variation and the movement speed of the substrate, b is a second calibration coefficient of the relationship between the line width of the first sub-linear mark and its position, dR is the line width of the first sub-linear mark (that is, the first sub-linear mark whose second position information is to be determined), and dL is the line width of another first sub-linear mark adjacent to the first sub-linear mark whose second position information is to be determined.

[0107] Therefore, when the movement direction of the substrate stage and the characteristic image have no non-orthogonal rotation, the relative translation and magnification of the time between two image acquisition positions (ie, the preset detection interval duration) can be analyzed by the above relationship (3).

[0108] The exposure method provided in this embodiment can also be applied to Figure 5The fifth exemplary embodiment of the dynamic alignment mark is shown. As mentioned above, in the fifth exemplary embodiment, the strip feature mark includes at least two linear combination marks spaced apart along the direction of movement of the substrate; each of the linear combination marks includes at least two second sub-linear marks spaced apart, and the extension direction of the second sub-linear marks is parallel to the direction of movement of the substrate; the distribution of the second sub-linear marks, the intervals between the second sub-linear marks, the number of the second sub-linear marks and / or the line width of at least one second sub-line mark of different linear combination marks are different. Therefore, the dynamic alignment mark adopts different combination forms along the scanning direction, and can simultaneously collect mark arrays with different combinations and different gaps within the set acquisition time, especially when continuously acquiring images at a uniform speed, the speed and the number of frames can be considered as invariants. Based on the changing acquisition results, the information of the scanning direction can be obtained by solving, so that the scanning direction position information obtained at the acquisition moment is more accurate, thereby laying a solid foundation for improving the exposure quality.

[0109] Optionally, in some exemplary embodiments, for each of the first sub-linear marks, the exposure method further includes calibrating the line width of the first sub-linear mark. Fig.10 and Fig.11 ,in, Fig.10 The overall flow chart of calibrating the line width of the first sub-linear mark in the exposure method provided by one embodiment of the present invention is as follows. Fig.11 for Fig.10 A specific example diagram of calibrating the line width of the first sub-linear mark. Fig.10 and Fig.11 It can be seen that the line width of the first sub-linear mark is calibrated by the following steps:

[0110] S001: in the process of correcting the first rotation angle between the first sub-linear mark and the moving direction of the substrate to be zero, acquiring a plurality of magnification test data of the image acquisition device;

[0111] S002: when the first rotation angle is zero and the substrate moves at a preset speed, collecting sub-linear images of the first sub-linear mark according to different first calibration sampling intervals, and calibrating multiple acquisition delay times of the image acquisition device during the acquisition process;

[0112] S003: correcting the magnification error of the image acquisition device according to the image acquisition delay time;

[0113] S004: when the first rotation angle is a different non-zero value and the substrate moves at a preset speed, collecting sub-linear images of the first sub-linear mark according to different second calibration sampling intervals, and calibrating the relationship between the first rotation angle and the line width of the first sub-linear mark during the collection process;

[0114] S005: Correcting the magnification coefficient of the image acquisition device according to the plurality of magnification test data and the magnification error;

[0115] S006: correcting a line width variation error of the first sub-linear mark according to a relationship between the first rotation angle and the line width of the first sub-linear mark and the magnification error;

[0116] S007: Calibrate the line width of the first sub-linear mark according to the corrected magnification coefficient and the corrected line width variation error. Fig.11 as well as Fig.12a , Figure 12b as well as Fig.12c The line width of the first sub-linear mark is exemplarily described as follows. Fig.12a Schematic diagram of image acquisition when there is Rv=0 in the moving direction of the dynamic alignment mark and the substrate stage; Figure 12b It is a rotation diagram in which the camera and the substrate stage have Rc≠Rv in their moving directions; Fig.12c This is a schematic diagram of dynamic alignment mark smear imaging. Fig.12a and Figure 12b As shown, the rotation Rc of the center line of the dynamic alignment mark and the camera (i.e., image acquisition device) field of view, and the calibration rotation Rv of the camera field of view and the movement direction of the substrate stage, Rz can be approximately calculated by Rc-Rv of a single acquisition, and its accuracy is related to the camera acquisition frame number / movement speed: pixel size. When the camera acquisition smear has an impact on the line width, the rotation is analyzed by the line width change of the smear. In order to facilitate the analysis of the characteristic pattern smear generated when the camera acquisition frequency is insufficient, it is assumed that the calibration Rv is true, so Rz≈Rc, equivalent to Rv≈0, such as Fig.12c The smear distribution shown can collect the line width change △d before and after. According to the number of collected frames F and the motion speed v of the motion stage, the theoretical length of the smear l=v / F can be calculated, and Rz≈△d / l can be approximately calculated.

[0117] In summary, compared with the prior art, the exposure method and exposure device provided by the present invention have the following advantages:

[0118] The exposure method provided by the present invention has a dynamic alignment system with a sensor (such as an image acquisition device), fast motion state update, and high automation rate. Compared with the static alignment measurement method in the prior art, the exposure method provided by the present invention can synchronously perform dynamic measurement during the scanning exposure process without frequently stopping the substrate stage for static mark alignment during the exposure process, avoiding frequent acceleration and deceleration of the substrate stage, thereby improving the productivity of the lithography equipment. In addition, the solution provided by the present invention can also be used in parallel with the static alignment system in the prior art, so that the lithography equipment has both static and dynamic alignment modes.

[0119] It should be noted that the devices and methods disclosed in the embodiments of this article can also be implemented in other ways. The device implementation described above is only schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of this article. In this regard, each box in the flowchart or block diagram can represent a part of a module, program or code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical function, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented by a dedicated hardware-based system for performing a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0120] In addition, the functional modules in the various embodiments of this document may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0121] The above description is only a description of the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any changes and modifications made by a person skilled in the art in the field of the present invention based on the above disclosure are within the scope of protection of the present invention. Obviously, a person skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An exposure method, wherein a mask and a substrate are synchronously moved in a first direction, and the substrate is exposed by a projection optical system, so that a pattern on the mask is transferred to the substrate; and a moving action which moves the substrate in a second direction orthogonal to the first direction; It is characterized by further comprising: A dynamic alignment system, wherein the dynamic alignment system is arranged opposite to a dynamic alignment mark arranged on the substrate or the substrate stage, the dynamic alignment mark is arranged in a long strip shape, and the length direction of the dynamic alignment mark is the first direction; the dynamic alignment mark is one of a single linear mark, at least two first sub-linear marks arranged at intervals along the moving direction of the substrate, and at least two linear combination marks arranged at intervals along the moving direction of the substrate; the length of the single linear mark is greater than or equal to the product of the preset detection interval time and the moving speed of the substrate; By means of the dynamic alignment system, the dynamic alignment mark is detected at a preset detection interval during the movement of the substrate along the first direction; The dynamic alignment system makes the positions of the mask and the substrate match based on the detection result.

2. The exposure method according to claim 1, characterized in that: The method of detecting the dynamic alignment mark with a preset detection interval duration during the movement of the substrate along the first direction by the dynamic alignment system includes: When the substrate stage is located at an initial position, obtaining first position information of the dynamic alignment mark in a coordinate system where the substrate is located; During the movement of the substrate, a characteristic image of the dynamic alignment mark is collected according to the preset detection interval duration; and second position information of the characteristic image in the coordinate system where the dynamic alignment system is located is obtained in real time; According to the coordinate conversion relationship between the coordinate system of the substrate and the coordinate system of the dynamic alignment system, the second position information is converted to the coordinate system of the substrate to obtain the third position information, and the detection result is obtained according to the initial position of the substrate, the third position information and the first position information.

3. The exposure method according to claim 2, characterized in that: Acquiring in real time the second position information of the characteristic image in the coordinate system where the dynamic alignment system is located, comprising: Processing the feature image using an image edge extraction method to obtain an edge image; Acquire second position information of the edge image in the coordinate system where the dynamic alignment system is located.

4. The exposure method according to claim 2, characterized in that: The dynamic alignment system includes an image acquisition device, and the maximum distance between the first sub-linear marks is smaller than the maximum field of view of the image acquisition device in the object side along the moving direction of the substrate.

5. The exposure method according to claim 4, characterized in that: The line widths of the first sub-linear marks are the same.

6. The exposure method according to claim 4, characterized in that: The line widths of the first sub-linear marks are different, and the real-time acquisition of the second position information of the characteristic image in the coordinate system where the dynamic alignment system is located includes: Obtaining second position information corresponding to the first sub-linear mark according to a first calibration coefficient of line width variation and movement speed of the substrate, a second calibration coefficient of a relationship between the line width of the first sub-linear mark and its position, and the line width of the first sub-linear mark; The line width change is the absolute value of the difference between the line width of the first sub-linear mark and the line width of another adjacent first sub-linear mark in the characteristic image.

7. The exposure method according to claim 6, characterized in that: Each of the linear combination marks includes at least two second sub-linear marks arranged at intervals, and the extension direction of the second sub-linear marks is parallel to the movement direction of the substrate; different linear combination marks have different distributions of the second sub-linear marks, intervals between the second sub-linear marks, the number of the second sub-linear marks and / or the line width of at least one of the second sub-linear marks.

8. The exposure method according to any one of claims 2 to 7, characterized in that: The coordinate conversion relationship between the coordinate system where the substrate is located and the coordinate system where the dynamic alignment system is located is calibrated when the substrate is in a stationary state.

9. The exposure method according to claim 6, characterized in that: For each of the first sub-linear marks, the exposure method further includes calibrating the line width of the first sub-linear mark by the following steps: In the process of correcting the first rotation angle between the first sub-linear mark and the moving direction of the substrate to be zero, acquiring a plurality of magnification test data of the image acquisition device; When the first rotation angle is zero and the substrate moves at a preset speed, the sub-linear images of the first sub-linear mark are collected according to different first calibration sampling intervals, and multiple acquisition delay times of the image acquisition device are calibrated during the acquisition process; Correcting the magnification error of the image acquisition device according to the image acquisition delay time; When the first rotation angle is a different non-zero value and the substrate moves at a preset speed, the sub-linear image of the first sub-linear mark is acquired according to different second calibration sampling intervals, and the relationship between the first rotation angle and the line width of the first sub-linear mark is calibrated during the acquisition process; Correcting the magnification coefficient of the image acquisition device according to the plurality of magnification test data and the magnification error; Correcting a line width variation error of the first sub-linear mark according to a relationship between the first rotation angle and the line width of the first sub-linear mark and the magnification error; The line width of the first sub-linear mark is calibrated according to the corrected magnification factor and the corrected line width variation error.

10. An exposure device comprising a mask stage for holding a mask, a substrate stage for holding a substrate, and a projection optical system, wherein the mask stage and the substrate stage are synchronously moved in a first direction while the substrate is exposed so that a pattern on the mask is transferred to the substrate; The substrate stage is movable along a second direction orthogonal to the first direction; It is characterized by further comprising: a dynamic alignment mark disposed on the substrate or the substrate stage, wherein the dynamic alignment mark is disposed in a long strip shape, and the length direction of the dynamic alignment mark is the first direction; the dynamic alignment mark is one of a single linear mark, at least two first sub-linear marks disposed at intervals along the moving direction of the substrate, and at least two linear combination marks disposed at intervals along the moving direction of the substrate; and the length of the single linear mark is greater than or equal to the product of the preset detection interval time length and the moving speed of the substrate; a dynamic alignment system, the dynamic alignment system being arranged opposite to the dynamic alignment mark and detecting the dynamic alignment mark at a preset detection interval during the movement of the substrate along the first direction; The dynamic alignment system makes the positions of the mask and the substrate match based on the detection result.

11. The exposure device according to claim 10, characterized in that The linear combination mark includes at least two second sub-linear marks arranged at intervals, and the extension direction of the second sub-linear marks is parallel to the movement direction of the substrate; the layout of the second sub-linear marks, the intervals between the second sub-linear marks, the number of the second sub-linear marks and / or the line width of at least one of the second sub-linear marks of the linear combination mark at different positions are different.

Images