Methods for measuring alignment deviation

Abstract

This application discloses a method for measuring alignment deviation, comprising: providing a substrate; sequentially stacking a third material layer, a second material layer, and a first material layer on the substrate, wherein a first alignment mark is provided on the first material layer, a second alignment mark is provided on the second material layer, and a third alignment mark is provided on the third material layer; measuring the alignment mark and the second alignment mark to obtain an alignment deviation X12 in a first direction and an alignment deviation Y12 in a second direction between the first alignment mark and the second alignment mark; measuring the alignment mark and the third alignment mark to obtain an alignment deviation X13 in the first direction and an alignment deviation Y13 in the second direction between the first alignment mark and the third alignment mark; determining a comprehensive deviation in at least one direction based on the deviations X12, X13, Y12, and Y13; the comprehensive deviation is used to characterize the overall deviation occurring in the corresponding direction. This application can accurately measure deviations during the etching process.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to a method for measuring alignment deviation. Background Technology

[0002] Overlay is a crucial process in semiconductor manufacturing. Overlay marks are used to identify alignment deviations during the overlay process, allowing for adaptive adjustments to relevant process parameters based on these deviations. Therefore, overlay marks play a vital role in ensuring the quality of the overlay process. However, traditional overlay marks are prone to measurement errors during rotational movements, resulting in low accuracy in identifying alignment deviations. Summary of the Invention

[0003] In view of this, this application provides a method for measuring alignment deviation, in order to solve the problem that traditional overlay marks are prone to measurement deviation when they undergo rotation, resulting in low accuracy of the final identified alignment deviation.

[0004] This application also provides a method for measuring alignment deviation, comprising the following steps:

[0005] A substrate is provided; a third material layer, a second material layer and a first material layer are stacked sequentially on the substrate, the first material layer is located on the upper surface of the second material layer, the second material layer is located on the upper surface of the third material layer, the first material layer is provided with a first alignment mark, the second material layer is provided with a second alignment mark, and the third material layer is provided with a third alignment mark;

[0006] The alignment deviation X12 in a first direction and the alignment deviation Y12 in a second direction are obtained by measuring the first alignment mark and the second alignment mark.

[0007] The alignment deviation X13 in a first direction and the alignment deviation Y13 in a second direction are obtained by measuring the first alignment mark and the third alignment mark; the first direction is perpendicular to the second direction.

[0008] Based on the deviations X12, X13, Y12, Y13, a comprehensive deviation in at least one direction is determined; the comprehensive deviation is used to characterize the overall deviation occurring in the corresponding direction.

[0009] Optionally, the comprehensive deviation includes a first comprehensive deviation corresponding to the first direction and a second comprehensive deviation corresponding to the second direction; the method for determining the first comprehensive deviation includes: X = Wx12*X12 + Wx13*X13; the method for determining the second comprehensive deviation includes: Y = Wy12*Y12 or Wy13*Y13; where Wx12 represents the weight of alignment deviation X12, Wx13 represents the weight of alignment deviation X13, X represents the first comprehensive deviation, Wy12 represents the weight of alignment deviation Y12, Wy13 represents the weight of alignment deviation Y13, and Y represents the second comprehensive deviation.

[0010] Optionally, Wx12 and Wx13 satisfy the following relationship: 0≤Wx12+Wx13≤1.

[0011] Optionally, Wy12 and Wy13 satisfy the following relationship: 0≤Wy12+Wy13≤1.

[0012] Optionally, if X12 / X13 is greater than 4 or less than 0.25, then Wx12 = 0 or Wx13 = 0;

[0013] If Y12 / Y13 is greater than 4 or less than 0.25, then Wy12 = 0 or Wy13 = 0.

[0014] Optionally, the alignment deviation X12, the alignment deviation X13, the alignment deviation Y12 and the alignment deviation Y13 form a set of deviations, and each alignment deviation in the set of deviations has a corresponding weight.

[0015] Optionally, the deviations include the following: offset, rotation, orthogonality, magnification, lithography error within the exposure area, or lithography error between exposure areas.

[0016] Optionally, the distance between the third alignment mark and the first alignment mark is used to measure the alignment deviation between the third material layer and the first material layer, and the distance between the second alignment mark and the first alignment mark is used to measure the alignment deviation between the second material layer and the first material layer.

[0017] Optionally, the distance between the third alignment mark and the first alignment mark includes the distance from a reference object in the third alignment mark to the corresponding reference object in the first alignment mark.

[0018] Optionally, the distance between the second alignment mark and the first alignment mark includes the distance from a reference object in the second alignment mark to the corresponding reference object in the first alignment mark.

[0019] Optionally, the center of the reference object is defined by a straight line determined by the center of the alignment mark where the reference object is located and the center of the first alignment mark.

[0020] The aforementioned method for measuring alignment deviation involves alignment marks on sequentially stacked material layers on a substrate forming a circular or centrally symmetrical structure. This ensures that even if the material layers and / or alignment marks rotate, the relative positions of the alignment marks between any two material layers remain unchanged. The alignment deviation measured based on the alignment marks on the two material layers remains stable before and after rotation, preventing measurement deviations and resulting in high accuracy. Furthermore, this method obtains alignment deviations X12 and Y12 in a first direction and a second direction between multiple sets of first and second alignment marks by measuring them. It also obtains alignment deviations X13 in a first direction and Y13 in a second direction between first alignment mark M1 and third alignment mark M3 by measuring them. Finally, it determines a comprehensive deviation in at least one direction based on deviations X12, X13, Y12, and Y13. This comprehensive deviation determination process covers multiple types of deviations in multiple directions, resulting in even higher accuracy. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the material layers with overlaid markings in one embodiment of this application;

[0023] Figure 2 This is a top view of the overprinted markings in one embodiment of this application;

[0024] Figure 3a , Figure 3b and Figure 3c This is a schematic diagram of the relevant structure of the overlay mark in one embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the relevant structure of the overlay mark in one embodiment of this application;

[0026] Figure 5a , Figure 5b , Figure 5c , Figure 5d and Figure 5e This is a schematic diagram of the relevant structure of the overlay mark in one embodiment of this application;

[0027] Figure 6 This is a schematic diagram of the alignment deviation measurement method in one embodiment of this application. Detailed Implementation

[0028] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0029] This application provides an overlay mark, for reference. Figure 1 and Figure 2 As shown, the overlay markings include alignment marks set on multiple material layers, such as reference markings. Figure 1 As shown, the overlay markings include the third material layer L1, the second material layer L2, ..., the (n-1)th material layer Ln-1 and the nth material layer Ln, for a total of n material layers. Figure 2 Alignment marks corresponding to each material layer are shown. For example, alignment marks may include the first alignment mark M1 corresponding to the third material layer L1, the second alignment mark M2 corresponding to the second material layer L2, ..., the (n-1)th alignment mark Mn-1 corresponding to the (n-1)th material layer Ln-1, and the nth alignment mark Mn corresponding to the nth material layer Ln. It should be noted that... Figure 1 , Figure 2 Furthermore, the accompanying drawings provided in this application only roughly illustrate the corresponding structures, and do not fully show all the components marked with overlays, nor do they show the relevant components in proportion.

[0030] In the above-mentioned overlay markings, at least one alignment mark on a material layer has a circular structure. Alignment marks set on any two material layers are used to measure the alignment deviation between the two material layers, so as to adjust the etching position in real time according to the alignment deviation and ensure the accuracy of the etching process.

[0031] Optionally, the alignment marks on each material layer are all circular. This ensures that the relative position between the alignment marks on any two material layers remains unchanged when the material layers and / or alignment marks are rotated. The alignment deviation measured based on the alignment marks on the two material layers remains stable before and after rotation, resulting in higher accuracy. Optionally, the centers of all the circular structures are on the same straight line, or in other words, the projections of the centers of all the circular structures onto the horizontal plane are on the same straight line.

[0032] In this embodiment, at least one alignment mark on a material layer has a circular structure; in one example, reference... Figure 1 and Figure 3a As shown, the alignment marks of the overlay markings can be circular structures. In another example, refer to... Figure 3b As shown, the alignment marks for the overlay markings can also be circular structures such as cylinders. Figure 3b Only the third material layer L1 and its corresponding first alignment mark M1, and the second material layer L2 and its corresponding second alignment mark M2 are shown. In another example, refer to... Figure 3c As shown, some alignment marks can be cylindrical, while others can be square or other structures with central symmetry. Because each alignment mark is circular or square, even if the material layers and / or alignment marks rotate, the relative positions of the alignment marks between any two material layers will not change. Therefore, the alignment deviation measured based on the alignment marks on the two material layers remains stable before and after rotation, resulting in higher accuracy.

[0033] Optionally, the nth material layer Ln may include a silicon substrate, or a conductive layer or an insulating layer. The third material layer L1 to the (n-1)th material layer Ln-1 may each include a semiconductor layer (such as a polysilicon layer). Alignment marks such as the first alignment mark M1, the second alignment mark M2, ..., the (n-1)th alignment mark Mn-1, and the nth alignment mark Mn may include recessed groove structures in the corresponding material layers, or protruding pillar structures protruding from the corresponding material layers, to provide reference marks for the corresponding material layers. Optionally, the alignment marks may be formed into circular patterns using positive or negative photoresist. Optionally, the first alignment mark M1 to the (n-1)th alignment mark Mn-1 may each include a recessed groove structure in the corresponding material layer, which may be formed using photolithography; the nth alignment mark Mn may include a cylindrical photoresist pattern protruding from the nth material layer Ln.

[0034] Specifically, the alignment deviation between the nth material layer Ln and the (n-1)th material layer Ln-1 can be characterized by the deviation between the centers of the nth alignment mark Mn and the (n-1)th alignment mark Mn-1. For example, refer to... Figure 4 As shown, if both the nth alignment mark Mn and the (n-1)th alignment mark are circular structures, the deviation between the center On of the nth alignment mark Mn and the center On-1 of the (n-1)th alignment mark can be used to characterize the alignment deviation between the nth material layer Ln and the (n-1)th material layer Ln-1.

[0035] Optionally, the number of material layers n in the overlay mark can be set according to the overlay requirements. For example, the number of layers n can be set to 3 or 4.

[0036] In one embodiment, the number of layers n is 3, in which case the multiple material layers include a third material layer L1, a second material layer L2, and a first material layer L3, such as Figure 5a As shown, the first material layer L1 is located on the surface of the second material layer L2, and the second material layer L2 is located on the surface of the third material layer L3.

[0037] The first material layer L1 has a first alignment mark M1, the second material layer L2 has a second alignment mark M2, and the third material layer L3 has a third alignment mark M3. The distance between the third alignment mark M3 and the first alignment mark M1 (e.g., distances d31 and d31') is used to measure the alignment deviation between the third material layer L3 and the first material layer L1. Specifically, the alignment deviation between the third material layer L3 and the first material layer L1 includes the difference between two different distances, for example, the alignment deviation may include d31-d31'. The distance between the second alignment mark M2 and the first alignment mark M1 (e.g., distances d21 and d21') is used to measure the alignment deviation between the second material layer L2 and the first material layer L1. Specifically, the alignment deviation between the second material layer L2 and the first material layer L1 includes the difference between two different distances, for example, the alignment deviation may include d21-d21'.

[0038] Optionally, the distance between the third alignment mark M3 and the first alignment mark M1 includes the distance from a reference object in the third alignment mark M3 to the corresponding reference object in the first alignment mark, for example, a reference... Figure 5b As shown, a reference object in the third alignment mark M3 is M3(1), and the corresponding reference object of M3(1) in the first alignment mark is M1(1). The distance between the third alignment mark M3 and the first alignment mark M1 includes the distance between M3(1) and M1(1).

[0039] Optionally, the distance between the second alignment mark M2 and the first alignment mark M1 includes the distance from a reference object in the second alignment mark M2 to the corresponding reference object in the first alignment mark M1, for example, a reference... Figure 5b As shown, a reference object in the second alignment mark M2 is M2(1), and the corresponding reference object of M2(1) in the first alignment mark is M1(1). The distance between the second alignment mark M2 and the first alignment mark M1 includes the distance between M2(1) and M1(1).

[0040] Optionally, the center of the reference object, the center of the alignment mark containing the reference object, and the center of the alignment mark containing the corresponding reference object are collinear. This allows the distance between the reference object and its corresponding reference object to more accurately represent the distance between corresponding material layers. Furthermore, as the material layers rotate, the relative positions of the corresponding reference objects collinear with their centers remain stable, which helps improve the accuracy of the obtained alignment deviation. Optionally, if the reference object includes a designated point, then the designated point and the center of the alignment mark containing the designated point are collinear. Optionally, if the reference object includes a designated circle, then the center of the designated circle and the center of the alignment mark containing the designated circle are collinear.

[0041] Optionally, the centers of the first alignment mark M1, the second alignment mark M2, and the third alignment mark M3 are projected onto the same straight line on the horizontal plane, for example, by referring to... Figure 5c In the top view shown, the center O1 of the first alignment mark M1, the center O2 of the second alignment mark M2, and the center O3 of the third alignment mark M3 are on the same straight line. A schematic diagram showing the alignment deviation at 0 can be found here. Figure 5b As shown. Reference Figure 5c The relevant distances shown can be used as a reference. Figure 5d As shown, the straight lines corresponding to each distance all pass through the center of the circle corresponding to the alignment mark to ensure the accuracy of the determined values. Specifically, Figure 5d The distances d21 and d21' between the second alignment mark M2 and the first alignment mark M1 are shown. At this time, the alignment deviation between the second alignment mark M2 and the first alignment mark M1 includes d21-d21'.

[0042] Optionally, the projections of the centers of the first alignment mark M1, the second alignment mark M2, and the third alignment mark M3 onto the horizontal plane may not lie on the same straight line, for example, referring to... Figure 5e As shown, Figure 5e Only the center O1 of the first alignment mark M1 is shown; the first alignment mark M1 itself is not shown. In this figure, the centers O1 of the first alignment mark M1, O2 of the second alignment mark M2, and O3 of the third alignment mark M3 are not on the same straight line. In this case, the alignment deviation between any two material layers can be accurately measured based on the alignment marks set on each of the two material layers.

[0043] Optionally, the third alignment mark, the second alignment mark, and the first alignment mark each include multiple arc segments located on the corresponding circular structure, so as to improve the distribution characteristics of each alignment mark and the flexibility in the formation process.

[0044] Furthermore, the reference object includes the center point of the corresponding arc segment, so that the reference object can more accurately represent the corresponding arc segment. The corresponding reference object of the reference object includes the center point of the arc segment corresponding to the arc segment in which the reference object is located, so that the distance between the reference object and its corresponding reference object can more accurately represent the distance between the corresponding alignment marks.

[0045] In one example, the first material layer L1 is aligned with the second material layer L2 and the third material layer L2, respectively; that is, the first alignment mark M1 of the first material layer L1 is aligned with the second alignment mark M2 of the second material layer L2, the first alignment mark M1 of the first material layer L1 is aligned with the third alignment mark M3 of the third material layer L3, and a reference object on the first alignment mark M1 is aligned with each reference object on the second alignment mark M2 and the third alignment mark M3, respectively; specifically, if the reference object includes a circle set within the alignment mark, the alignment can represent that the centers of the corresponding set of circles representing the reference objects are on the same straight line; optionally, the straight line passes through the center of the overprint mark.

[0046] There is a first deviation between the first material layer and the second material layer, and a second deviation between the first material layer and the third material layer. The first deviation can characterize at least one of the following deviations between the first and second material layers: offset, rotation, orthogonality, amplification, intrafield residual error, or interfield residual error. The second deviation can characterize at least one of the following deviations between the first and third material layers: offset, rotation, orthogonality, amplification, intrafield residual error, or interfield residual error.

[0047] In the above overlay markings, at least one alignment mark on a material layer has a circular structure. This ensures that even if the material layer and / or the alignment mark rotate, the relative position between the alignment marks on any two material layers will not change. The alignment deviation measured based on the alignment marks on the two material layers can remain stable before and after the rotation of the material layer and / or the alignment mark, without generating measurement deviation. The obtained alignment deviation has high accuracy. Using this to calibrate the deviation during the etching process helps to improve the precision of the corresponding etching process.

[0048] This application also provides a method for measuring alignment deviation, which can be achieved using the overlay marks provided in any of the above embodiments. (Reference) Figure 6The above-mentioned method for measuring alignment deviation includes the following steps S110 to S140.

[0049] S110, providing a substrate; reference Figures 5a to 5b As shown, the substrate is sequentially stacked with a third material layer L3, a second material layer L2, and a first material layer L1. The first material layer L1 is located on the upper surface of the second material layer L2, the second material layer L2 is located on the upper surface of the third material layer L3, the first material layer L1 is provided with a first alignment mark M1, the second material layer L2 is provided with a second alignment mark M2, and the third material layer L3 is provided with a third alignment mark M3.

[0050] S120, Measure the first alignment mark M1 and the second alignment mark M2 to obtain the alignment deviation X12 in the first direction and the alignment deviation Y12 in the second direction between the first alignment mark M1 and the second alignment mark M2. Here, multiple sets of reference objects for the first alignment mark M1 and the second alignment mark M2 can be measured to obtain the alignment deviation X12 and the alignment deviation Y12 respectively; for example, a set of reference objects in the first direction can be measured to obtain the alignment deviation X12, and another example is that a set of reference objects in the second direction can be measured to obtain the alignment deviation Y12.

[0051] S130, Measure the first alignment mark M1 and the third alignment mark M3 to obtain the alignment deviation X13 in the first direction and the alignment deviation Y13 in the second direction between the first alignment mark M1 and the third alignment mark M3; the first direction is perpendicular to the second direction; here, multiple sets of reference objects of the first alignment mark M1 and the third alignment mark M3 can be measured to obtain the alignment deviation X13 and the alignment deviation Y13 respectively; for example, a set of reference objects in the first direction can be measured to obtain the alignment deviation X13, and another example is that a set of reference objects in the second direction can be measured to obtain the alignment deviation Y13.

[0052] S140, determine a comprehensive deviation in at least one direction based on the deviations X12, X13, Y12, Y13; the comprehensive deviation is used to characterize the overall deviation occurring in the corresponding direction.

[0053] The above-described method for measuring alignment deviation employs the overlay mark measurement provided in any of the above embodiments, resulting in higher reliability in the measurement process. By measuring multiple sets of first alignment marks M1 and second alignment marks M2, the alignment deviation X12 in the first direction and the alignment deviation Y12 in the second direction between the first alignment marks M1 and the second alignment marks M2 are obtained. By measuring the first alignment marks M1 and the third alignment marks M3, the alignment deviation X13 in the first direction and the alignment deviation Y13 in the second direction between the first alignment marks M1 and the third alignment marks M3 are obtained. Then, based on the deviations X12, X13, Y12, and Y13, a comprehensive deviation in at least one direction is determined. This process of determining the comprehensive deviation covers multiple types of deviations in multiple directions, resulting in higher accuracy.

[0054] In one embodiment, the overall deviation includes a first overall deviation corresponding to a first direction and a second overall deviation corresponding to a second direction; the method for determining the first overall deviation includes: X = Wx12*X12 + Wx13*X13; the method for determining the second overall deviation includes: Y = Wy12*Y12 or Wy13*Y13; where Wx12 represents the weight of alignment deviation X12, Wx13 represents the weight of alignment deviation X13, X represents the first overall deviation, Wy12 represents the weight of alignment deviation Y12, Wy13 represents the weight of alignment deviation Y13, and Y represents the second overall deviation. This embodiment can accurately calculate the overall deviation in each direction.

[0055] Optionally, Wx12 and Wx13 satisfy the following relationship: 0 ≤ Wx12 + Wx13 ≤ 1. The Wx12 and Wx13 determined here have higher accuracy.

[0056] Optionally, Wy12 and Wy13 satisfy the following relationship: 0 ≤ Wy12 + Wy13 ≤ 1. The Wy12 and Wy13 determined here have higher accuracy.

[0057] Optionally, if X12 / X13 is greater than 4 or less than 0.25, then Wx12 = 0 or Wx13 = 0; specifically, if the deviation ratio X12 / X13 is greater than 4, Wx13 = 0; if the deviation ratio X12 / X13 is less than 0.25, Wx12 = 0.

[0058] Optionally, if Y12 / Y13 is greater than 4 or less than 0.25, then Wy12 = 0 or Wy13 = 0. Specifically, if the deviation ratio Y12 / Y13 is greater than 4, Wy13 = 0; if the deviation ratio Y12 / Y13 is less than 0.25, Wy12 = 0.

[0059] Optionally, the alignment deviation X12, the alignment deviation X13, the alignment deviation Y12 and the alignment deviation Y13 can form a set of deviations, and each alignment deviation in each set of deviations has a corresponding weight.

[0060] Optionally, the deviations include the following: offset, rotation, orthogonality, magnification, intrafield residual error within the exposure area, or interfield residual error between exposure areas.

[0061] In one embodiment, the distance between the third alignment mark and the first alignment mark is used to measure the alignment deviation between the third material layer and the first material layer, and the distance between the second alignment mark and the first alignment mark is used to measure the alignment deviation between the second material layer and the first material layer.

[0062] In one embodiment, the distance between the third alignment mark and the first alignment mark includes the distance from a reference object in the third alignment mark to the corresponding reference object in the first alignment mark.

[0063] In one embodiment, the distance between the second alignment mark and the first alignment mark includes the distance from a reference object in the second alignment mark to the corresponding reference object in the first alignment mark.

[0064] Optionally, the center of the reference object is defined by a straight line determined by the center of the alignment mark where the reference object is located and the center of the first alignment mark.

[0065] The above-described method for measuring alignment deviation, using the overlay marks provided in any of the above embodiments, possesses all the beneficial effects of the overlay marks provided in any of the above embodiments, and will not be elaborated further here. Furthermore, this measurement method obtains the alignment deviation X12 in the first direction and the alignment deviation Y12 in the second direction between the first alignment mark M1 and the second alignment mark M2 by measuring multiple sets of first alignment marks M1 and second alignment marks M2; it also obtains the alignment deviation X13 in the first direction and the alignment deviation Y13 in the second direction between the first alignment mark M1 and the third alignment mark M3 by measuring the first alignment mark M1 and the third alignment mark M3; and then determines the comprehensive deviation in at least one direction based on the deviations X12, X13, Y12, and Y13. This allows the determination process of the comprehensive deviation to cover multiple types of deviations in multiple directions, resulting in higher accuracy.

[0066] Although this application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art based on a reading and understanding of this specification and drawings. This application includes all such modifications and variations and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the aforementioned components, the terminology used to describe such components is intended to correspond to any component (unless otherwise indicated) that performs the specified function of said component (e.g., is functionally equivalent to it), even if it is not necessarily structurally equivalent to the disclosed structure that performs the functions in the exemplary implementations of this specification shown herein.

[0067] That is, the above description is only an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, such as the combination of technical features between different embodiments, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of this application.

[0068] Furthermore, it should be understood that in the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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 this application. Additionally, for structural elements with the same or similar characteristics, this application may use the same or different reference numerals for identification. Moreover, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0069] In this application, the term "exemplary" is used to mean "serving as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as more preferred or advantageous than other embodiments. This application has been provided above to enable any person skilled in the art to implement and use it. Various details have been set forth in the above description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be implemented without using these specific details. In other embodiments, well-known structures and processes will not be described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed herein.

Claims

1. A method of measuring misalignment, characterized by, The method comprises the following steps: providing a substrate; sequentially stacking a third material layer, a second material layer and a first material layer on the substrate, the first material layer being on the upper surface of the second material layer, the second material layer being on the upper surface of the third material layer, the first material layer being provided with a first alignment mark, the second material layer being provided with a second alignment mark, and the third material layer being provided with a third alignment mark; the first alignment mark, the second alignment mark and the third alignment mark are all center-symmetric structures; measuring the first alignment mark and the second alignment mark to obtain alignment deviation X12 in a first direction and alignment deviation Y12 in a second direction between the first alignment mark and the second alignment mark; measuring the first alignment mark and the third alignment mark to obtain alignment deviation X13 in the first direction and alignment deviation Y13 in the second direction between the first alignment mark and the third alignment mark; the first direction is perpendicular to the second direction; determining a comprehensive deviation in at least one direction according to the deviations X12, X13, Y12 and Y13; the comprehensive deviation is used to represent the overall deviation in the corresponding direction; the comprehensive deviation comprises a first comprehensive deviation corresponding to the first direction and a second comprehensive deviation corresponding to the second direction; the method for determining the first comprehensive deviation comprises X=Wx12*X12+Wx13*X13; the method for determining the second comprehensive deviation comprises Y=Wy12*Y12 or Wy13*Y13; in the formula, Wx12 represents the weight of the alignment deviation X12, Wx13 represents the weight of the alignment deviation X13, X represents the first comprehensive deviation, Wy12 represents the weight of the alignment deviation Y12, Wy13 represents the weight of the alignment deviation Y13, and Y represents the second comprehensive deviation.

2. The method of measuring alignment deviation according to claim 1, wherein, The Wx12 and the Wx13 satisfy the following relationship: 0≤Wx12+Wx13≤1.

3. The method of claim 1, wherein, The Wy12 and the Wy13 satisfy the following relationship: 0≤Wy12+Wy13≤1.

4. The method of claim 1, wherein, If X12 / X13 is greater than 4 or less than 0.25, then Wx12=0 or Wx13=0. If Y12 / Y13 is greater than 4 or less than 0.25, then Wy12=0 or Wy13=0.

5. The method of claim 1, wherein The alignment deviations X12, X13, Y12 and Y13 form a group of deviations, and each alignment deviation in each group of deviations has a corresponding weight; The groups of deviations comprise the following deviations: offset, rotation, orthogonality, magnification, lithography error in an exposure area or lithography error between exposure areas.

6. The method of claim 1, wherein The distance between the third alignment mark and the first alignment mark is used to measure the alignment deviation between the third material layer and the first material layer, and the distance between the second alignment mark and the first alignment mark is used to measure the alignment deviation between the second material layer and the first material layer.

7. The method of claim 1, wherein The distance between the third alignment mark and the first alignment mark comprises the distance between a reference object in the third alignment mark and the corresponding reference object of the reference object in the first alignment mark.

8. The method of claim 1, wherein, The distance between the second alignment mark and the first alignment mark includes a distance from a reference object in the second alignment mark to a corresponding reference object in the first alignment mark.

9. The method of measuring alignment deviation according to claim 7 or 8, wherein, A straight line defined by a center of the alignment mark in which the reference object is located and a center of the first alignment mark defines a center of the reference object.

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