Method and system for judging overlay error

Abstract

The present disclosure relates to a method and system for determining an overlay error, including setting a reference pattern module above a substrate. The substrate includes first and second overlay measurement patterns located at first and second positions. The reference pattern module includes first and second reference patterns. The method includes creating a first overlap between the first reference pattern and the first overlay measurement pattern, and creating a second overlap between the second reference pattern and the second overlay measurement pattern. The method also includes determining a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, and determining a second overlay error between the second reference pattern and the second overlay measurement pattern. The method also determines an overall overlay error between the first and second overlay measurement patterns of the substrate based on the first and second overlay errors.

Description

Technical Field

[0001] The present disclosure relates to a method for determining an overlay error, and more particularly to a method for determining an overlay error by using a reference pattern module. Background Art

[0002] As the semiconductor industry moves toward nanotechnology process nodes in pursuit of higher device density, reducing the overlay error between a photoresist layout pattern and an underlying layout pattern during lithography has become one of the most important issues. Therefore, an effective method is needed to accurately determine the overlay error between a photoresist layout pattern and one of the underlying layout patterns. Summary of the invention

[0003] The disclosed embodiment provides a method for measuring overlay error. The method includes setting a reference pattern module above a substrate. The substrate includes a first overlay measurement pattern located at a first position, and a second overlay measurement pattern located at a second position and separated from the first overlay measurement pattern. The reference pattern module includes a first reference pattern and a second reference pattern separated from the first reference pattern. The method includes at least creating a first reference pattern overlapping with a first portion of the first overlay measurement pattern below the reference pattern module, and while creating the first portion of the overlap, at least creating a second reference pattern overlapping with a second portion of the second overlay measurement pattern below the reference pattern module. The method also includes determining a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, determining a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate, and determining an overall overlay error between the first overlay measurement pattern and the second overlay measurement pattern of the substrate based on the first overlay error and the second overlay error.

[0004] The disclosed embodiment provides a method for measuring overlay error. The method includes performing a first analysis on a first diffraction light combination of a first reference pattern received from a reference pattern module and a first overlay measurement pattern received from a first position of a first thin layer of a substrate to determine a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate. The method also includes performing a second analysis on a second diffraction light combination of a second reference pattern received from the reference pattern module and a second overlay measurement pattern received from a second position of a second thin layer of the substrate to determine a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate. The method also includes determining an overall overlay error between the first overlay measurement pattern and the second overlay measurement pattern based on the first overlay error and the second overlay error.

[0005] The embodiment of the present disclosure provides a system for determining an overlay error. The system includes a main controller and a reference pattern module disposed above a substrate, the substrate including a first overlay measurement pattern located in a first position of the substrate, and a second overlay measurement pattern located in a second position of the substrate. The system includes an analyzer module coupled to the main controller. The analyzer module receives a first reference pattern and a second reference pattern. The system includes a layout generator coupled to the main controller, and is configured to receive the first reference pattern and the second reference pattern from the analyzer module via the main controller, and receive an offset between the first reference pattern and the second reference pattern. The layout generator is also coupled to the reference pattern module, and generates the first reference pattern and the second reference pattern in the reference pattern module. The system includes a stage controller coupled to the main controller to control the movement of the substrate, and includes an optical system, the optical system including one or more light sources and coupled to the main controller. The one or more light sources generate a first light beam to illuminate the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate. The one or more light sources generate a second light beam to illuminate the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate. The optical system also includes one or more light detectors, and the one or more light detectors receive a first diffraction light combination from the first overlay measurement pattern and the first reference pattern, and receive a second diffraction light combination from the second overlay measurement pattern and the second reference pattern. The analyzer module also receives a detection signal related to the first diffraction light combination to determine a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, and receives a detection signal related to the second diffraction light combination to determine a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present disclosure can be better understood from the following embodiments and the accompanying drawings. It should be emphasized that, in accordance with standard industry practice, various features are not drawn to scale and are only used for illustrative purposes. In fact, the size of various features may be arbitrarily increased or decreased for clarity of discussion.

[0007] Figure 1A and Figure 1B According to some embodiments of the present disclosure, a top view and a cross-sectional view of an overlay measurement pattern generated on a wafer by a beam lithography system are respectively shown.

[0008] Figure 2A and Figure 2B According to some embodiments of the present disclosure, cross-sectional views of a substrate having two overlay measurement patterns are respectively shown, and Figure 2B An optical system for determining an overlay error between two overlay measurement patterns on a substrate is included.

[0009] Figure 3A , Figure 3B and Figure 3C According to some embodiments of the present disclosure, a substrate having two overlay measurement patterns wherein one of the overlay measurement patterns has an overlay offset (drift), positive first-order and negative first-order diffraction light intensities as functions of the overlay offset, and a difference in first-order diffraction light intensity as a function of the overlay offset are respectively displayed.

[0010] Figure 4 is an exemplary overlay measurement pattern shown according to some embodiments of the present disclosure.

[0011] Figure 5A , Figure 5B , Figure 5C and Figure 5D According to some embodiments of the present disclosure, a substrate having two overlay measurement patterns, a cross-sectional view of a reference pattern module, a top view of the reference pattern module, and a cross-sectional view of the reference pattern module above the substrate are respectively shown.

[0012] Fig. 6A and Figure 6B According to some embodiments of the present disclosure, a measurement system for determining overlay error is shown.

[0013] Fig. 7A , Figure 7B and Figure 7C According to some embodiments of the present disclosure, a reference pattern group of reference patterns is displayed.

[0014] Figure 8 An exemplary measurement system for determining overlay error according to some embodiments of the present disclosure is shown.

[0015] Fig. 9 is a flow chart of an exemplary process for determining overlay error according to some embodiments of the present disclosure.

[0016] Fig. 10A and Fig. 10B According to some embodiments of the present disclosure, a device for determining an overlay error is shown.

[0017] The reference numerals are described as follows:

[0018] 100: Overlay measurement pattern

[0019] 112: Y direction

[0020] 113: Width

[0021] 114: Dark Stripe

[0022] 116: Bright bar

[0023] 117: Length

[0024] 119: Height

[0025] 124: X direction

[0026] 132: Spacing

[0027] 134: Width

[0028] 136: Z direction

[0029] 200: Substrate

[0030] 202: Second thin layer

[0031] 203: Photoresist layer

[0032] 204: First thin layer

[0033] 206: Second overlay measurement pattern

[0034] 208: First overlay measurement pattern

[0035] 232: Substrate

[0036] 210: First-order diffraction

[0037] 210A: Negative first-order diffraction

[0038] 210B: Negative first-order diffraction

[0039] 212: First-order diffraction

[0040] 212A: Positive first-order diffraction

[0041] 212B: Positive first-order diffraction

[0042] 214A: Incident beam

[0043] 214B: The remainder

[0044] 220: Optical system

[0045] 222: Detector

[0046] 226: Light Source

[0047] 230: Analyzer module

[0048] 302: Offset distance

[0049] 304: Intensity coordinates

[0050] 320: AS function

[0051] 322: Slope

[0052] 400: Overlay measurement pattern

[0053] 401: Upper left part

[0054] 402: Upper right part

[0055] 404: Lower left part

[0056] 405: Lower right part

[0057] -D: Initial offset

[0058] +D: Initial offset

[0059] 502A: Reference pattern

[0060] 502B: Reference pattern

[0061] 504: LCD panel

[0062] 506: Support fixture

[0063] 510A: Secondary pattern

[0064] 510B: Secondary pattern

[0065] 520: Layout Generator Controller

[0066] 532A: Spacing

[0067] 532B: Spacing

[0068] 534A: Width

[0069] 534B: Width

[0070] 550: Reference pattern module

[0071] 552: Bottom surface

[0072] 554: Top surface

[0073] 556: Distance

[0074] 508: Length

[0075] 302A: Offset distance

[0076] 302B: Offset distance

[0077] 558: Distance

[0078] 514: Incident beam

[0079] 515: Incident beam

[0080] 542: Negative first-order diffraction

[0081] 544: Negative first-order diffraction

[0082] 546: Positive first-order diffraction

[0083] 548: Positive first-order diffraction

[0084] 551: Carrier

[0085] 560: Stage controller

[0086] 602: Substrate

[0087] 606: Spectroscope

[0088] 650: Incident beam

[0089] 652: Part 1

[0090] 654: Combined post-diffraction

[0091] 656: Part 2

[0092] 700: Reference pattern group

[0093] 701: Reference pattern

[0094] 710: Substrate

[0095] 720: Substrate

[0096] 750: Reference pattern group

[0097] 503A: Reference pattern

[0098] 503B: Reference pattern

[0099] 513A: Secondary pattern

[0100] 513B: Secondary pattern

[0101] 521: Layout Position Controller

[0102] 553: Reference pattern module

[0103] 555: Substrate

[0104] 800: System

[0105] 802: Stage controller

[0106] 804: Optical System

[0107] 806: Layout Position Controller

[0108] 808: Layout Generator

[0109] 810: Layout Pattern

[0110] 830: Analyzer module

[0111] 840: Main Controller

[0112] 900: Process

[0113] S902~S912: Operation

[0114] 1000: Computer Systems

[0115] 1001: Computer

[0116] 1002: Keyboard

[0117] 1003: Mouse

[0118] 1004: Display

[0119] 1005: CD-ROM drive

[0120] 1006: Disk drive

[0121] 1011: Processor

[0122] 1012: ROM

[0123] 1013: Random Access Memory

[0124] 1014: Hard disk

[0125] 1015: Bus

[0126] 1021: CD

[0127] 1022: Disk DETAILED DESCRIPTION

[0128] The following disclosure provides many different embodiments or examples for implementing different features of the present disclosure. Specific examples of the various components and arrangements of the present disclosure are described below to simplify the description. Of course, these examples are not intended to limit the present disclosure. For example, if the description has a first feature formed on or above a second feature, it may include an embodiment in which the first feature and the second feature are formed in direct contact, and it may also include an embodiment in which an additional feature is formed between the first feature and the second feature so that the first feature and the second feature are not in direct contact. In addition, the present disclosure may repeat reference numbers and / or letters in multiple examples. The purpose of this repetition is to simplify and clarify, and does not itself specify the relationship between the various embodiments and / or configurations discussed.

[0129] Further, the present disclosure may use spatially relative terms, such as "below," "below," "below," "above," "above," and the like, to describe the relationship between one element or feature and other elements or features in the diagram. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the diagram. The device may be turned to different orientations (rotated 90 degrees or other orientations), and the spatially relative terms used herein may be interpreted accordingly. In addition, the term "made of" may mean "comprising" or "consisting of." In the present disclosure, the phrase "one of A, B, and C" means "A, B, C, A and B, A and C, B and C, or A and B and C," and does not mean one element from A, one element from B, and one element from C unless otherwise specified.

[0130] During integrated circuit (IC) design, many IC layout patterns are generated for different steps in the IC process. The layout pattern includes the geometric shape corresponding to the structure to be manufactured on the wafer. The layout pattern can be a mask layout pattern, which is projected (e.g., imaged) on the wafer to create the IC. The lithography process transfers the layout pattern of the mask to the wafer so that etching, implantation, or other operations are only applied to predefined areas of the wafer. Multiple layout patterns can be transferred to different thin layers of the wafer to create different structures on the wafer. Therefore, when the first or previous layout pattern exists in a different first thin layer of the wafer below the second thin layer, the second or subsequent layout pattern can be transferred to the second thin layer on the wafer.

[0131] As described above, multiple layout patterns can be transferred to different thin layers of a wafer to create different structures on the wafer. Ideally, there is no overlay error between the layout patterns generated on the wafer. In some embodiments, an overlay measurement pattern (e.g., grating) is included in each layout pattern. The overlay measurement pattern (which may not be part of the IC circuit) is used to determine the overlay error between different layout patterns set on the wafer. In some embodiments, the overlay error between two layout patterns of the wafer is measured when the overlay measurement patterns of the two layout patterns overlap. The overlay measurement patterns of the two layout patterns are irradiated with a light beam (e.g., a coherent beam of light), and the overlay error between the two layout patterns is determined (e.g., calculated) based on the diffracted light reflected from the overlay measurement patterns of the two layout patterns.

[0132] In some embodiments, a first layout pattern including a first overlay measurement pattern is imaged (e.g., projected) onto a wafer to create a first layout pattern and a first overlay measurement pattern on a first thin layer of the wafer. In some embodiments, the first thin layer is covered by a second thin layer, and a second layout pattern including a second overlay measurement pattern is created in the second thin layer. The second thin layer is initially covered by a resist material layer, and the second layout pattern including the second overlay measurement pattern is imaged on the resist material layer on top of the second thin layer. Thus, the second overlay measurement pattern is located in the resist material layer, and the resist material layer is located on top of the second thin layer, and the second thin layer is located on top of the first thin layer including the first overlay measurement pattern. In some other embodiments, the second thin layer does not exist, and the first thin layer is covered by the resist material layer, and the second layout pattern including the second overlay measurement pattern is imaged onto the resist material layer directly on top of the first thin layer. Thus, the second overlay measurement pattern is located in the photoresist layer, and the photoresist layer is located on top of the first thin layer, wherein the first thin layer includes the first overlay measurement pattern. In either case, after developing the photoresist material, if the first overlay measurement pattern of the first thin layer overlaps with the second overlay measurement pattern of the photoresist layer on top of the first thin layer, the overlay error between the first layout pattern and the second layout pattern can be measured. In some embodiments, when the overlay error is below a threshold, the developed photoresist material including the second layout pattern is used for the next process operation. Otherwise, the photoresist material is removed and a new photoresist layout pattern is formed in a lithography process with a corrected alignment.

[0133] As described above, the overlay error can be measured when the first overlay measurement pattern of the first thin layer overlaps with the second overlay measurement pattern of the photoresist layer. In some embodiments, each layout pattern includes a plurality of overlay measurement patterns to ensure that overlap occurs in at least one position where strong diffraction light is generated, wherein the strong diffraction light is reflected back from the overlapped overlay measurement pattern. In some embodiments, a reference pattern module including one or more reference patterns is disposed on the wafer. Instead of overlapping the overlay measurement pattern of the photoresist layer with the overlay measurement pattern of the thin layer below the photoresist to determine the overlay error, the overlay error of each layer of the substrate (including the photoresist layer) is determined by using the reference pattern module. Therefore, the creation of overlap between the overlay measurement pattern of the photoresist layer and the thin layer below the photoresist layer is avoided, and the creation of multiple overlay measurement patterns in the layout pattern of the thin layer is also avoided.

[0134] In some embodiments, the reference pattern module includes a liquid crystal display (LCD) panel having a top transparent plate, a bottom transparent plate, and liquid crystals surrounded by the top and bottom transparent plates. Top and bottom electrodes are disposed on the inner surfaces of the top and bottom transparent plates to generate a pattern on the LCD panel. In addition, polarizers are disposed on the top and bottom transparent plates to polarize each other with a polarization phase shift of 90 degrees.

[0135] In some embodiments, one or more desired reference patterns are generated in the LCD panel by applying a voltage between specific portions of the top electrode and the bottom electrode. In some embodiments, the one or more desired reference patterns generated are identical to the overlay measurement pattern of the thin layer of the substrate. In some embodiments, the light transmission between the top surface and the bottom surface can be adjusted between 0.1% and 0.99% by adjusting the voltage applied between the top electrode surface and the bottom electrode surface of the LCD panel. In some embodiments, a portion of the light incident from the top surface is diffracted by the reference pattern in the LCD panel generated in the reference pattern module. In some embodiments, a portion of the light incident from the top surface is diffracted and reflected by the reference pattern in the LCD panel generated in the reference pattern module.

[0136] In some embodiments, the reference pattern module is disposed above the substrate, and the substrate has a first overlay measurement pattern in a first thin layer of the substrate, and a second overlay measurement pattern in a photoresist layer on top of the first thin layer. The liquid crystal panel of the reference pattern module can generate a reference pattern that overlaps with the first overlay measurement pattern of the first thin layer. Similarly, the liquid crystal panel of the reference pattern module can generate another reference pattern that overlaps with the second overlay measurement pattern of the photoresist layer. In some embodiments, the overlay error is measured in the following manner: First, the reference pattern module is disposed above the first thin layer and the photoresist layer. Next, a primary reference pattern that overlaps with the first overlay measurement pattern of the first thin layer is generated in the reference pattern module. Then, a secondary reference pattern that overlaps with the second overlay measurement pattern of the photoresist layer is generated in the reference pattern module. Thereafter, a first overlay error between the primary reference pattern and the first overlay measurement pattern is measured, and a second overlay error between the secondary reference pattern and the second overlay measurement pattern is measured. Next, based on the first overlay error and the second overlay error, the overlay error between the layout pattern of the first thin layer and the layout pattern of the photoresist layer is determined. In some embodiments, the overlay error between the layout pattern of the first thin layer and the layout pattern of the photoresist material layer is also determined based on the information of the reference pattern module, for example, based on the distance between the primary reference pattern and the secondary reference pattern, and additionally based on the expected distance between the first overlay measurement pattern and the second overlay measurement pattern.

[0137] Figure 1A and Figure 1B According to some embodiments of the present disclosure, a top view and a cross-sectional view of an overlay measurement pattern generated on a wafer by a beam lithography system are respectively shown. Figure 1A The overlay measurement pattern 100 is shown extending in the Y direction 122 with a length 117 and distributed in the X direction 124 with a width 113. The overlay measurement pattern 100 includes a dark strip 114 and a bright strip 116. In some embodiments, when an incident light beam illuminates the overlay measurement pattern 100, the dark strip 114 is a low-reflection portion, and the bright strip 116 is a high-reflection portion.

[0138] Figure 1BA cross-sectional view of the overlay measurement pattern 100 is shown extending in the Z direction 136 with a height 119 and distributed in the X direction 124. In some embodiments, the dark stripes 114 are features of a thin layer (e.g., a photoresist pattern) that remain after a lithography process is applied, and the light stripes 116 are locations that are removed after the lithography process is applied. In other embodiments, for example, depending on the material of the underlying thin layer, the dark pattern and the light pattern are opposite. As shown in the cross-sectional view, the dark stripes 114 have a width 134, such as a critical dimension (CD), and the overlay measurement pattern 100 has a pitch 132. In some embodiments, when the wavelength of the incident light beam is comparable to the width 134 and / or the pitch 132 of the overlay measurement pattern, the incident light beam is diffracted and a portion of the incident light beam is reflected back. The diffraction of the incident light beam will be referenced to Figure 2B Have a discussion.

[0139] Figure 2A and Figure 2B A cross-sectional view of a substrate 232 having two overlay measurement patterns: an overlay measurement pattern 206 and an overlay measurement pattern 208 is shown. Figure 2B According to some embodiments of the present disclosure, an optical system 220 for determining an overlay error between two overlay measurement patterns of a substrate is further shown. Figure 2A The cross-sectional view includes an overlay measurement pattern 208 in a first thin layer 204 disposed on top of a substrate 200 below. In some embodiments, the overlay measurement pattern 208 together with a corresponding circuit layout pattern (not shown) is initially disposed on the substrate 200 below, and then the first thin layer 204 is disposed (e.g., epitaxially grown or deposited) on the overlay measurement pattern 208. In some embodiments, the second thin layer 202 is disposed (e.g., epitaxially grown or deposited) on the first thin layer 204. In some embodiments, a photoresist material layer 203 is deposited on the second thin layer 202, and the photoresist material layer 203 is exposed and developed to produce an overlay measurement pattern 206 and a corresponding layout pattern (not shown) in the photoresist material layer 203. In some embodiments, the overlay measurement pattern 206 and the overlay measurement pattern 208, and Figure 1A and Figure 1B The overlay measurement pattern 100 is consistent with Figure 1A and Figure 1BSimilarly, the overlay measurement pattern 206 and the overlay measurement pattern 208 are distributed in the X direction to measure the overlay error in the X direction. In some embodiments, an overlay measurement pattern distributed in the Y direction is also provided to measure the overlay error in the Y direction. In some embodiments, the second thin layer 202 does not exist, and the overlay measurement pattern 206 is provided on top of the first thin layer 204. In some embodiments, the substrate 232 includes a substrate 200 below, and a structure on top of the substrate 200 below, the structure including the first thin layer 204, the second thin layer 202, and the photoresist layer 203.

[0140] Figure 2B An optical system 220 is shown, which includes one or more light sources 226 and one or more detectors 222 . Figure 2A Also shown are the overlay measurement pattern 206, the overlay measurement pattern 208, the first thin layer 204, the second thin layer 202, and the photoresist material layer 203. In some embodiments, the light source 226 of the optical system 220 emits (e.g., irradiates) an incident light beam 214A to the overlay measurement pattern 206 and the overlay measurement pattern 208 that overlap in the X direction and the Y direction. In some embodiments, the overlay measurement pattern 206 and the overlay measurement pattern 208 have the same pitch, and the light source 226 (being a coherent light source) has a wavelength comparable to the pitch of the overlay measurement patterns 206 and 208. A portion of the incident light beam 214A is diffracted and reflected from the overlay measurement pattern 206, and generates a negative first order diffraction 210A and a positive first order diffraction 212A. The remaining portion 214B of the incident light beam 214A passes through the overlay measurement pattern 206, and is diffracted and reflected from the overlay measurement pattern 208, and generates a negative first-order diffraction 210B and a positive first-order diffraction 212B. Therefore, the reflected first-order diffraction 210 including the negative first-order diffraction 210A and 210B is detected by one detector 222, and the reflected first-order diffraction 212 including the positive first-order diffraction 212A and 212B is detected by another detector 222.

[0141] Figure 2B The analyzer module 230 is shown coupled to the optical system 220. The analyzer module 230 receives the corresponding signals of the detected first-order diffractions 210 and 212 and performs analysis on the corresponding signals to determine the drift (eg, shift) between the overlay measurement pattern 208 and the overlay measurement pattern 206.

[0142] In some embodiments, the first thin layer 204 includes an overlay measurement pattern 208 as a part of a first layout pattern. Similarly, the photoresist layer 203 deposited on the second thin layer 202 includes an overlay measurement pattern 206 as a part of a second layout pattern. Therefore, the lateral position difference between the overlay measurement pattern 208 and the overlay measurement pattern 206 represents the lateral position difference between the first layout pattern of the first thin layer 204 and the second layout pattern to be created in the second thin layer 202 using the photoresist layer 203. In some embodiments, the top overlay measurement pattern 206 and the bottom overlay measurement pattern 208 have the same pitch and the same shape, so that the number of boxes (e.g., sub-patterns of the overlay measurement pattern), the width of the boxes, and the distance between the boxes in the overlay measurement patterns 206 and 208 are the same. In some embodiments, the top overlay measurement pattern 206 coincides with the bottom overlay measurement pattern 208, such that the boxes in the overlay measurement patterns 206 and 208 coincide, and there is no drift between the boxes of the top overlay measurement pattern 206 and the boxes of the bottom overlay measurement pattern 208. In some embodiments, due to the numerical aperture of the optical system 220, such as the numerical aperture of the detector 222, the first order diffraction 210 and 212 enter the detector, while the higher order diffraction does not enter the optical system 220.

[0143] Figure 3A , Figure 3B and Figure 3C According to some embodiments of the present disclosure, a substrate 232 having two overlay measurement patterns 206 and 208 is shown, wherein one of the overlay measurement patterns has an overlay offset ( Figure 3A ), the negative first-order diffraction 210 (also referred to as the first-order diffraction 210) and the positive first-order diffraction 212 (also referred to as the first-order diffraction 212) as a function of the overlay offset ( Figure 3B ), and the difference in first-order diffraction light intensity as a function of the offset distance 302 of the overlay pair ( Figure 3C ). Figure 3A and Figure 2A The difference is that the overlay measurement pattern 206 of the photoresist material layer 203 on top of the second thin layer 202 is offset in the positive X direction by an offset distance 302 relative to the overlay measurement pattern 208. The offset distance 302 is the distance between the centers (e.g., the centroid or the center of the center pattern) of the two overlay measurement patterns 206 and 208.

[0144] Figure 3B The light intensity of the negative first order diffraction 210 and the positive first order diffraction 212 is shown as a function of the offset distance 302 of the overlay pair. In some embodiments, Figure 3BThe signals corresponding to the detected negative first-order diffraction 210 and positive first-order diffraction 212 are respectively displayed, wherein the negative first-order diffraction 210 and the positive first-order diffraction 212 are represented by Figure 2B In some embodiments, the analyzer module 230 receives the corresponding signals of the detected first-order diffraction 210 and 212, and removes the signal corresponding to the negative first-order diffraction 210 from the signal corresponding to the positive first-order diffraction 212 to generate an asymmetry (AS) function 320 ( Figure 3C ).like Figure 3B As shown, the signal corresponding to the negative first-order diffraction 210 has an intensity peak in the negative region of the offset distance 302, while the signal corresponding to the positive first-order diffraction 212 has an intensity peak in the positive region of the offset distance 302. Figure 3B The signals corresponding to the detected negative first-order diffraction 210 and positive first-order diffraction 212 are shown to be symmetric with respect to the intensity coordinate 304. Although the offset distance 302 is shown as an offset between the edges of the boxes of the overlay measurement patterns 206 and 208, the origin of the overlay measurement patterns 206 and 208 can be defined as the center of the overlay measurement patterns 206 and 208, and the offset distance 302 can be defined relative to the offset of the center of the overlay measurement patterns 206 and 208.

[0145] Figure 3C The AS function 320 is shown as a function of the offset distance 302. Because the signals corresponding to the detected negative first-order diffraction 210 and positive first-order diffraction 212 are symmetric with respect to the intensity coordinate 304, the AS function 320 passes through the origin. In some embodiments, the AS function can be written as:

[0146]

[0147] Where P is the pattern (grating) pitch, S is the offset distance 302, and k is determined based on the wavelength of light and the thin layer structure (e.g., thickness, refractive index, and absorption coefficient) of the first thin layer, the second thin layer, and the photoresist material layer. In some embodiments, when the offset distance 302 is smaller than the pattern pitch P, the AS function can be written as:

[0148]

[0149] in AS function 320 is in Figure 3C The slope at the origin in is 322.

[0150] Figure 4 According to some embodiments of the present disclosure, exemplary overlay measurement patterns are shown. Figure 4The overlay measurement pattern 400 may be used as the overlay measurement pattern 206 and may be generated in the photoresist material layer, and the overlay measurement pattern 400 has four different overlay measurement patterns. In some embodiments, when the overlay measurement pattern 400 on the top is overlapped with the overlay measurement pattern 208 on the bottom, the upper right portion 402 and the lower left portion 404 of the overlay measurement pattern 400 have initial offsets of -D and +D in the positive X direction, respectively, relative to the overlay measurement pattern 208 on the bottom. In some embodiments, the overlay measurement pattern 400 on the top is placed above the overlay measurement pattern 208 on the bottom with an overlay error OV in the X direction (e.g., overlay placement error in the X direction), and thus the AS function between the upper right portion 402 and the overlay measurement pattern 208 on the bottom becomes:

[0151]

[0152] This is Figure 3C The AS function between the upper right portion 402 and the overlay measurement pattern 208 at the bottom can be approximated as AS1=K.(OV-D), which is Figure 3C The AS function 320 has a point with an offset S=(OV-D) on the slope 322. In addition, the AS function between the lower left portion 404 and the overlay measurement pattern 208 at the bottom becomes:

[0153]

[0154] This is Figure 3C The AS function between the lower left portion 404 and the overlay measurement pattern 208 at the bottom can be approximated as AS2=K.(OV+D), which is Figure 3C The slope 322 of the AS function 320 has a point with an offset S=(OV+D). Therefore, by using Figure 2B By using the optical system 220 and measuring the detected negative first-order diffraction 210 and the positive first-order diffraction 212, an AS function value AS1 between the upper right portion 402 of the overlay measurement pattern 400 and the bottom overlay measurement pattern 208 can be determined, and an AS function value AS2 between the lower left portion 404 of the overlay measurement pattern 400 and the bottom overlay measurement pattern 208 can be determined, and the overlay error OV in the X direction can be determined as:

[0155]

[0156] In some embodiments, when the overlay measurement pattern 400 on the top overlaps with the overlay measurement pattern 208 on the bottom, the upper left portion 401 and the lower right portion 405 of the overlay measurement pattern 400 respectively have initial offsets of -D and +D in the positive Y direction relative to the overlay measurement pattern 208 on the bottom. Therefore, the overlay error in the Y direction may be determined in a similar manner.

[0157] In some embodiments and Figure 1A and Figure 1B As shown, the width 113 of each portion of the overlay measurement pattern 400 is between 300 nm (nanometers) and 40,000 nm. The CD of the sub-pattern (e.g., box) of each portion of the overlay measurement pattern 400 is between 10 nm and 1400 nm. The spacing between the sub-patterns of each portion of the overlay measurement pattern 400 is between 100 nm and 1500 nm.

[0158] Figure 5A , Figure 5B , Figure 5C and Figure 5D According to some embodiments of the present disclosure, a substrate 232 having two overlay measurement patterns 206 and 208 , a cross-sectional view of a reference pattern module, a top view of the reference pattern module, and a cross-sectional view of the reference pattern module above the substrate are respectively shown. Figure 5A and Figure 3A 2. The overlay measurement pattern 206 and the bottom overlay measurement pattern 208 are identical, except that the top overlay measurement pattern 206 and the bottom overlay measurement pattern 208 are located in different and non-overlapping portions of the substrate. As shown, the top overlay measurement pattern 206 and the bottom overlay measurement pattern 208 are located in different positions on the substrate 200 or the thin layer below, and may not be adjacent to each other. As described above, the overlay measurement pattern 208 is part of the first layout pattern of the first thin layer 204, while the overlay measurement pattern 206 is created in the photoresist material layer 203 on top of the second thin layer 202, wherein the second thin layer 202 is disposed on the first thin layer 204. Also as described above, in some embodiments, the second thin layer 202 does not exist, and the photoresist material layer 203 is disposed on top of the first thin layer 204.

[0159] Figure 5B5 is a cross-sectional view of a reference pattern module 550, which is an LCD panel 504 having a top surface 554 and a bottom surface 552. In some embodiments, the LCD panel 504 is an LCD flat panel having a plurality of pixels, and each pixel is controlled by at least one thin film transistor (TFT). In some embodiments, the layout generator controller 520 includes a display card for generating signals that are applied to the TFTs to turn on / off the pixels of the LCD panel to create sub-patterns 510A and 510B (e.g., rectangular boxes) in the LCD panel. In some embodiments, each of the sub-patterns 510A and 510B includes a plurality of pixels, wherein each pixel is located between the top surface 554 and the bottom surface 552. The TFT transistors can change the transmittance of the pixels to generate the sub-patterns 510A and 510B. In some embodiments, when an incident light beam illuminates the reference pattern 502A and the reference pattern 502B, the dark sub-patterns 510A and 510B are low-reflection portions, while the bright boxes adjacent to the sub-patterns 510A and 510B are high-reflection portions. Therefore, if a voltage (e.g., a signal) is applied to the TFTs controlling the sub-patterns 510A and 510B, the transmittance of the sub-patterns 510A and 510B can be changed. Therefore, by applying a voltage between the TFT transistors of the sub-patterns 510A and 510B to produce a desired pattern, a group of sub-patterns 510A can be used as the reference pattern 502A, and a group of sub-patterns 510B can be used as the reference pattern 502B. Figure 5B and Figure 5C As shown, reference pattern 502A and reference pattern 502B may not be adjacent to each other. In some embodiments, sub-pattern 510A (e.g., box) of reference pattern 502A has width 534A and spacing 532A, while sub-pattern 510B (e.g., box) of reference pattern 502B has width 534B and spacing 532B. In some embodiments, reference pattern module 550 is supported by support fixture 506.

[0160] The layout generator controller 520 is coupled to the reference pattern module 550. In some embodiments, the layout generator controller 520 generates signals to be applied to the TFT transistors controlling the sub-patterns 510A and 510B to generate the reference patterns 502A and 502B of the reference pattern module 550. In some embodiments, the layout generator controller 520 controls the position of the reference pattern module 550 in the X direction and / or the Y direction. In some embodiments, by turning on / off the TFT transistors, the layout generator controller 520 moves the reference patterns 502A and 502B at the pixel resolution of the LCD panel.

[0161] In some embodiments, the distance 556 between the center (e.g., the centroid or center of the center pattern) of the reference pattern 502A and the center of the reference pattern 502B is fixed, known, or preset. In some embodiments, the distance 556 is a known expected distance between the centers of the overlay measurement pattern 206 and the overlay measurement pattern 208 of the substrate 232. In some embodiments, the TFT transistors are turned on and off to change the transmittance of the pixels of the LCD panel between transparent (e.g., bright) to opaque (e.g., dark).

[0162] In some embodiments and according to the characteristics of the liquid crystal material between the top surface 554 and the bottom surface 552, the reference pattern module 550 displays the reference patterns 502A and 502B by applying a positive voltage of 5 volts to the top surface contacts of the sub-patterns 510A and 510B and applying a ground voltage to the bottom surface contacts of the sub-patterns 510A and 510B. Therefore, the reference pattern module 550 is capable of not allowing a light beam incident perpendicularly from the top surface of the sub-patterns 510A and 510B to leave the bottom surface of the sub-patterns 510A and 510B. In some embodiments, the positive voltage applied to the top surface contacts is reduced so that a portion of the light beam incident perpendicularly from the top surface of the sub-patterns 510A and 510B leaves the bottom surface of the sub-patterns 510A and 510B. In some embodiments, a portion of the light incident from the top surface is diffracted and reflected by one or more overlay measurement patterns generated by the sub-patterns 510A and 510B in the reference pattern module 550.

[0163] Figure 5C is a top view of the reference pattern module 550 and shows reference patterns 502A and 502B generated by the layout generator controller 520 in the reference pattern module 550. In some embodiments, the sub-pattern 510A has a uniform width 534A and / or the sub-pattern 510B has a uniform width 534B, and the width 534A is different from the width 534B. In some embodiments, the reference pattern 502A has a uniform spacing 532A between every two adjacent sub-patterns 510A, and / or the reference pattern 502B has a uniform spacing 532B between every two adjacent sub-patterns 510B, and the spacing 532A is different from the spacing 532B. In some embodiments, at least one of the widths 534A of the sub-patterns 510A of the reference pattern 502A and / or at least one of the widths 534B of the sub-patterns 510B of the reference pattern 502B are different. In some embodiments, at least one of the spacings 532A between every two adjacent sub-patterns 510A of the reference pattern 502A and / or at least one of the spacings 532B between every two adjacent sub-patterns 510B of the reference pattern 502B are different.

[0164] In some embodiments, the layout generator controller 520 generates the reference pattern module 550 in accordance with Figure 4 In some embodiments, the layout generator controller 520 generates a plurality of reference patterns consistent with the overlay measurement pattern 400 at different positions of the reference pattern module 550, such that at least two of the reference patterns are not adjacent to each other. In some embodiments, the reference pattern module 550 has a length 508 in the Y direction.

[0165] Figure 5D is a cross-sectional view of a reference pattern module 550 placed above a substrate 232. As shown in the figure, the reference pattern 502A is offset by an offset distance 302A (e.g., overlay error) relative to the overlay measurement pattern 208 of the substrate 232 in the negative X direction, and thus the offset distance 302A is a negative distance. In addition, the reference pattern 502B is offset by an offset distance 302B (e.g., overlay error) relative to the overlay measurement pattern 206 of the substrate 232 in the positive X direction, and thus the offset distance 302B is a positive distance. Therefore, the total overlay offset distance (total overlay error) between the overlay measurement pattern 206 and the overlay measurement pattern 208 is the difference between the offset distance 302A and the offset distance 302B, and because the offset distance 302A and the offset distance 302B have different polarities, the values ​​are added to each other.

[0166] In some embodiments, the offset distance 302A and the offset distance 302B have the same polarity (not shown). The overall overlay offset distance (overall overlay error) between the overlay measurement pattern 206 and the overlay measurement pattern 208 is the difference between the offset distance 302A and the offset distance 302B, and because the offset distance 302A and the offset distance 302B have the same polarity, the values ​​are subtracted from each other.

[0167] In some embodiments, the overlay measurement pattern 206 is a part of the first layout pattern, and the overlay measurement pattern 208 is a part of the second layout pattern. Therefore, by determining (e.g., measuring) the overall overlay error between the overlay measurement pattern 206 and the overlay measurement pattern 208, the overlay error between the first layout pattern and the second layout pattern can be determined.

[0168] like Figure 5DAs shown, the center-to-center distance between the reference pattern 502A and the reference pattern 502B is distance 556, and the center-to-center distance between the overlay measurement pattern 206 and the overlay measurement pattern 208 is distance 558. Because the offset distance 302A and the offset distance 302B have opposite polarities, the difference between the distance 556 and the distance 558 has a value that is the sum of the absolute values ​​of the offset distance 302A and the offset distance 302B.

[0169] Fig. 6A and Figure 6B According to some embodiments of the present disclosure, a measurement system for determining overlay error is shown. Fig. 6A Display substrate 602, wherein substrate 602 and Figure 5A 5. The substrate 602 is mounted on a stage 551, and the stage 551 is coupled to and controlled by a stage controller 560. The reference pattern module 550 is also mounted on and above the surface of the substrate 602, and is parallel to the stage 551. In some embodiments, the layout generator controller 520 moves the reference patterns 502A and 502B to a specific position (e.g., by turning on / off the TFT transistor), and / or the stage controller 560 moves the substrate 602, so that the reference patterns 502A and 502B generated by the layout generator controller 520 overlap (e.g., at least partially overlap) with the overlay measurement patterns 206 and 208 of the substrate 602. In some embodiments, the reference pattern 502A overlaps with the overlay measurement pattern 208 of the first thin layer 204, and the reference pattern 502B overlaps with the overlay measurement pattern 206 of the photoresist material layer 203. By measuring the relative position between the overlay measurement pattern 208 and the reference pattern 502A, and measuring the relative position between the overlay measurement pattern 206 and the reference pattern 502B, the overlay error between the overlay measurement pattern 206 and the overlay measurement pattern 208 can be measured. This is because the distance (e.g., center-to-center distance) between the reference pattern 502A and the reference pattern 502B is known or preset.

[0170] In such Fig. 6AIn some embodiments shown, a light source of the optical system 220 emits an incident light beam 514 toward the overlay measurement pattern 208 and the reference pattern 502A, wherein the overlay measurement pattern 208 and the reference pattern 502A have overlap at least in the X direction. In some embodiments, the overlay measurement pattern 208 and the reference pattern 502A have the same pitch. A portion of the incident light beam 514 is diffracted and reflected from the reference pattern 502A, and generates a negative first-order diffraction and a positive first-order diffraction, which are inner portions of the first-order diffraction 542 and the first-order diffraction 546, respectively. The remaining portion of the incident light beam 514 passes through the reference pattern 502A, and is diffracted and reflected from the overlay measurement pattern 208, and generates a negative first-order diffraction and a positive first-order diffraction, which are outer portions of the first-order diffraction 542 and the first-order diffraction 546, respectively. The reflected negative first-order diffraction 542 (also referred to as the first-order diffraction 542 ) and the positive first-order diffraction 546 (also referred to as the first-order diffraction 546 ) are detected by the detector 222 of the optical system 220 .

[0171] Fig. 6A An analyzer module 230 coupled to the optical system 220 is also shown. The analyzer module 230 receives the corresponding signals of the detected first-order diffractions 542 and 546 and performs analysis on the corresponding signals to determine a first drift (e.g., a first overlay error) between the overlay measurement pattern 208 and the reference pattern 502A. As described above, in some embodiments, the wavelength of the incident light beam 514 is comparable to the spacing between the reference pattern 502A and the overlay measurement pattern 208. In addition, in some embodiments, the wavelength of the incident light beam 515 is comparable to the spacing between the reference pattern 502B and the overlay measurement pattern 206. Therefore, when the overlay measurement patterns 208 and 206 have different spacings, two different light sources of the optical system 220 with different wavelengths are used to generate the incident light beams 514 and 515. In some embodiments, when the overlay measurement patterns 208 and 206 have the same spacing, the same light source or two different light sources of the optical system 220 can be used to generate the incident light beams 514 and 515.

[0172] In addition, if Fig. 6AAs shown, a light source of the optical system 220 emits an incident light beam 515 toward the overlay measurement pattern 206 and the reference pattern 502B, wherein the overlay measurement pattern 206 and the reference pattern 502B have an overlap at least in the X direction. In some embodiments, the overlay measurement pattern 206 and the reference pattern 502B have the same spacing, which is different from the spacing between the overlay measurement pattern 208 and the reference pattern 502A. A portion of the incident light beam 515 is diffracted and reflected from the reference pattern 502B, and generates a negative first-order diffraction and a positive first-order diffraction, which are the inner portions of the first-order diffraction 544 and the first-order diffraction 548, respectively. The remaining portion of the incident light beam 515 passes through the reference pattern 502B, and is diffracted and reflected from the overlay measurement pattern 206, and generates a negative first-order diffraction and a positive first-order diffraction, which are the outer portions of the first-order diffraction 544 and the first-order diffraction 548, respectively. The reflected negative first-order diffraction 544 (also referred to as the first-order diffraction 544) and the positive first-order diffraction 548 (also referred to as the first-order diffraction 548) are detected by the detector 222 of the optical system 220. The analyzer module 230 receives the corresponding signals of the detected first-order diffraction 544 and 548, and performs analysis on the corresponding signals to determine the second drift (e.g., the second overlay error) between the overlay measurement pattern 206 and the reference pattern 502B. As described above, the wavelength of the light beam irradiating the overlay reference pattern 502B and the overlay measurement pattern 206, and the wavelength of the light beam irradiating the overlay reference pattern 502A and the overlay measurement pattern 208 are comparable to the spacing between the overlay measurement patterns 206 and 208.

[0173] In some embodiments, the layout generator controller 520 has information of the reference patterns 502A and 502B, including the distance between the generated reference patterns 502A and 502B. In some embodiments, the overlap between the overlay measurement pattern 208 and the reference pattern 502A, and the overlap between the overlay measurement pattern 206 and the reference pattern 502B are concurrent. In some embodiments, the distance between the generated reference patterns 502A and 502B is the expected distance between the overlay measurement patterns 206 and 208. Therefore, the analyzer module 230 can determine the overlay error between the overlay measurement pattern 206 and the overlay measurement pattern 208 based on the first and second overlay errors.

[0174] In some embodiments, the overlap between the overlay measurement pattern 208 and the reference pattern 502A, and the overlap between the overlay measurement pattern 206 and the reference pattern 502B do not occur simultaneously. In addition, the analyzer module 230 receives the distance between the generated reference patterns 502A and 502B from the layout generator controller 520, receives the movement of the stage 551 from the stage controller 560, and receives the position of the reference pattern module 550 from the layout generator controller 520. Therefore, the analyzer module 230 can determine the overall overlay error between the overlay measurement pattern 206 and the overlay measurement pattern 208 based on the first and second overlay errors, the distance between the reference patterns 502A and 502B, and the movement distance of the reference pattern module 550 and the stage 551. Therefore, in some embodiments, the reference patterns 502A and 502B of the reference pattern module 550 are generated on the fly, and the width and spacing of the reference patterns 502A and 502B are selected based on the overlay measurement patterns 206 and 208. In some embodiments, the pitch of the reference pattern 502A and the reference pattern 502B is adjusted to increase the diffraction signal detected by the detector. In some embodiments, the pitch of the reference pattern 502A and the reference pattern 502B is adjusted to match the corresponding pitch of the overlay measurement pattern 206 and the overlay measurement pattern 208.

[0175] Figure 6B Display substrate 602, substrate 602 and Figure 5A The substrate 602 is mounted on the stage 551, and the stage 551 is coupled to the stage controller 560 and controlled by the stage controller 560. The reference pattern module 550 is mounted on the top of the substrate 602 and is perpendicular to the stage 551. Figure 6B Also shown is a beam splitter 606 that receives the incident light beam 650 and generates a first portion 652 parallel to the incident light beam and a second portion 656 perpendicular to the incident light beam from the incident light beam 650. In some embodiments, the layout generator controller 520 moves the reference patterns 502A and 502B to specific positions (e.g., by turning on / off TFT transistors), and / or the stage controller 560 moves the substrate 602, so that the first portion 652 of the incident light beam 650 is incident on the reference pattern 502B, and the second portion 656 of the incident light beam 650 is incident on the overlay measurement pattern 206.

[0176] In some embodiments, a first portion 652 of the incident light beam 650 is diffracted and reflected from the reference pattern 502B, and generates a negative first-order diffraction 210A and a positive first-order diffraction 212A. A second portion 656 of the incident light beam 650 is diffracted and reflected from the overlay measurement pattern 206, and generates a negative first-order diffraction 210B and a positive first-order diffraction 212B. In some embodiments, an optical system (e.g., a beam splitter 606) receives the negative first-order diffraction 210A and the positive first-order diffraction 212A from the reference pattern 502B, and receives the negative first-order diffraction 210B and the positive first-order diffraction 212B from the overlay measurement pattern 206, and the optical system combines the received diffraction and sends the combined diffraction 654 to the detector 222 of the optical system 220. In some embodiments, the diffraction angle of the negative first-order diffraction 210A and the positive first-order diffraction 212A from the reference pattern 502B is very small, for example, less than 30 degrees. The diffraction angles of the negative first-order diffraction 210B and the positive first-order diffraction 212B from the overlay measurement pattern 206 are also small. Therefore, the beam splitter 606 can combine the first-order diffraction patterns from the reference pattern 502B and the overlay measurement pattern 206. In some embodiments, an optical system (e.g., an objective lens, not shown) is disposed in front of the reference pattern 502B and the overlay measurement pattern 206. The optical system collects the first-order diffraction and guides the first-order diffraction to be combined. The negative first-order diffraction and the positive first-order diffraction of the combined diffraction 654 are detected by the detector 222 of the optical system 220. The analyzer module 230 receives the corresponding signal of the detected first-order diffraction and analyzes the corresponding signal to determine the second drift between the overlay measurement pattern 206 and the reference pattern 502B, such as the second overlay error.

[0177] In some embodiments, the layout generator controller 520 moves the reference patterns 502A and 502B to specific positions (e.g., by turning on / off TFT transistors), and / or the stage controller 560 moves the substrate 602, so that the first portion 652 of the incident light beam 650 is incident on the reference pattern 502A, and the second portion 656 of the incident light beam 650 is incident on the overlay measurement pattern 208. Similarly, the analyzer module 230 determines a first overlay error between the overlay measurement pattern 208 and the reference pattern 502A. Furthermore, the analyzer module 230 may determine an overall overlay error between the overlay measurement pattern 206 and the overlay measurement pattern 208 based on the first overlay error and the second overlay error, the distance between the generated reference patterns 502A and 502B, and the movement distance of the reference pattern module 550 and the stage 551. In some embodiments, instead of or in addition to moving the substrate 602 and / or the reference pattern module 550 , the beam splitter 606 is also moved left-right and / or up-down.

[0178] Fig. 7A , Figure 7B and Figure 7C According to an embodiment of the present disclosure, a reference pattern group of reference patterns is displayed. Fig. 7A A reference pattern group 700 is shown, and the reference pattern group 700 includes Figure 4 The reference patterns 701 of the reference pattern group 700 are consistent with the overlay measurement pattern, and have multiple widths and spacings arranged along the edge of the substrate 710. In some embodiments, for example, the reference patterns 701 of the reference pattern group 700 are disposed on the substrate 710 by oxide growth, patterning by photolithography, and etching.

[0179] Figure 7B A reference pattern group 750 is shown, which includes a plurality of reference patterns 701 having a plurality of widths and pitches arranged in a substrate 720. In some embodiments, for example, the reference patterns 701 of the reference pattern group 750 are disposed on the substrate 750 by oxide growth, patterning by lithography, and etching.

[0180] Figure 7C A cross-sectional view of the reference pattern module 553 is shown, wherein the reference pattern module 553 and Figure 5B The reference pattern module 553 is created by setting sub-patterns (boxes) 513A and 513B on substrate 555. Reference pattern module 553 is not a liquid crystal panel, and sub-patterns (boxes) 513A and 513B of reference pattern module 553 are created by oxide growth, oxide patterning, and oxide etching. However, sub-patterns (boxes) 513A and 513B are consistent with sub-patterns (boxes) 510A and 510B, and reference patterns 503A and 503B are consistent with reference patterns 502A and 502B, respectively. In some embodiments, Fig. 6A and Figure 6B The measurement system may use reference pattern module 553 instead of reference pattern module 550. Figure 6B , Figure 7CThe layout position controller 521 and / or the stage controller 560 moves the substrate 602 and / or the reference pattern module 553 so that the first portion 652 of the incident light beam 650 is incident on the selected reference pattern 503A of the reference pattern module 553, and the second portion 656 of the incident light beam 650 is incident on the overlay measurement pattern 208. In addition, the layout position controller 521 and / or the stage controller 560 moves the substrate 602 and / or the reference pattern module 553 so that the first portion 652 of the incident light beam 650 is incident on the reference pattern 503B of the reference pattern module 553, and the second portion 656 of the incident light beam 650 is incident on the overlay measurement pattern 206. In some embodiments, the reference patterns 503A and 503B are not adjacent to each other.

[0181] Figure 8 According to some embodiments of the present disclosure, a measurement system for determining overlay error is shown. The system 800 includes an analyzer module 830 and a main controller 840 coupled to each other. Figure 2B , Fig. 6A , Figure 6B The analyzer module 230 is consistent with the analyzer module 830, receiving the Figure 5B and Figure 5C The analyzer module 830 may be directly connected to the optical system 804, or may be connected to the optical system 804 via a main controller 840.

[0182] In some embodiments, the main controller 840 is coupled to the layout generator 808, the layout position controller 806, the optical system 804, and the stage controller 802. Figure 2B , Fig. 6A and Figure 6B , the optical system 804 is consistent with the optical system 220. The optical system 804 controlled by the main controller 840 generates Figure 2B , Fig. 6A and Figure 6B The incident light beams 214A, 514, 515 and 650 are received by the optical system 804. In addition, the optical system 804 receives the diffracted light from the overlay measurement pattern and detects the diffracted light, and generates a corresponding signal of the detected diffracted light. The optical system 804 sends the corresponding signal of the detected diffracted light to the analyzer module for analysis as described above with respect to Fig. 6A and Figure 6B The above analysis is generally performed to determine the drift between different overlay measurement patterns of the substrate. In some embodiments, Figure 5B , Fig. 6A and Figure 6B The layout generator controller 520 is consistent with the combination of the layout position controller 806 and the layout generator 808. In some embodiments, Figure 7CThe layout position controller 521 is consistent with the layout position controller 806. In some embodiments, the layout position controller 806 is incorporated into the layout generator 808, and by turning on / off the TFT transistors, the layout generator 808 moves the reference pattern at the pixel resolution of the LCD panel.

[0183] In some embodiments, the analyzer module 830 sends one or more layout patterns 810 to the layout generator 808 directly or via the main controller 840 and instructs the layout generator 808 to generate the layout patterns 810 in the following manner: Figure 5B , Figure 5C , Fig. 6A and Figure 6B One or more layout patterns 810 are created in the reference pattern module 550 .

[0184] Fig. 9 According to some embodiments of the present disclosure, a flowchart of an exemplary process 900 for determining overlay error is shown. The process 900 may be Fig. 6A , Figure 6B and Figure 8 In some embodiments, a portion of process 900 is performed and / or controlled by a computer system 1000, which will be referred to below. Fig. 10A and Fig. 10B The method includes operation S902, in which a reference pattern module including a first reference pattern and a second reference pattern is disposed above the substrate. Figure 5B As shown in FIG. 5 , the reference pattern module 550 includes a first reference pattern 502A (also referred to as reference pattern 502A) and a second reference pattern 502B (also referred to as reference pattern 502B). Fig. 6A and Figure 6B As shown, the reference pattern module 550 is placed on (eg, above) the substrate 602. In some embodiments, the substrate 602 includes a first overlay measurement pattern 206 (also referred to as the overlay measurement pattern 206) and a second overlay measurement pattern 208 (also referred to as the overlay measurement pattern 208).

[0185] In operation S904, at least a first partial overlap is created between the first reference pattern and the first overlay measurement pattern of the substrate. Fig. 6A As shown, an overlay is created between the first reference pattern 502A of the reference pattern module 550 and the first overlay measurement pattern 208 of the substrate 602 .

[0186] In operation S906, at least a second partial overlap is created between the second reference pattern and the second overlay measurement pattern of the substrate. Fig. 6AAs shown, an overlay is created between the second reference pattern 502B of the reference pattern module 550 and the second overlay measurement pattern 206 of the substrate 602. In some embodiments, operations S904 and S906 are performed simultaneously.

[0187] In operation S908, a first layout error between the first reference pattern and the first overlay measurement pattern is determined. Fig. 6A As shown, the optical system 220 transmits an incident light beam 514 to the first reference pattern 502A, wherein the first reference pattern 502A is located on top of the first overlay measurement pattern 208. First order diffractions 542 and 546 reflected from the first reference pattern 502A and from the first overlay measurement pattern 208 are detected by the optical system 220, and the detected signals are transmitted to the analyzer module 230. The analyzer module 230 determines (e.g., calculates) a first layout error between the first overlay measurement pattern 208 and the first reference pattern 502A based on the detected signals.

[0188] In operation S910, a second layout error between a second reference pattern and a second overlay measurement pattern is determined. Fig. 6A As shown, the optical system 220 transmits an incident light beam 515 to the second reference pattern 502B, wherein the second reference pattern 502B is located on top of the second overlay measurement pattern 206. The first order diffractions 544 and 548 reflected from the second reference pattern 502B and from the second overlay measurement pattern 208 are detected by the optical system 220, and the detected signals are transmitted to the analyzer module 230. The analyzer module 230 calculates a second layout error between the second overlay measurement pattern 206 and the second reference pattern 502B based on the detected signals.

[0189] In operation S912, an overall layout error between the first overlay measurement pattern and the second overlay measurement pattern of the substrate is determined. The overall layout error between the first overlay measurement pattern 208 and the second overlay measurement pattern 206 is determined by the analyzer module 230. In some embodiments, as described above, the overall layout error is an algebraic sum of the first and second layout errors, such as addition or subtraction.

[0190] Fig. 10A and Fig. 10B According to some embodiments of the present disclosure, a device for determining an overlay error is shown. Fig. 10Ais a schematic diagram of a computer system 1000, which executes a process for determining overlay errors according to one or more of the above-described embodiments. All or part of the processes, methods and / or operations of the aforementioned embodiments may be implemented using computer hardware and computer software executed thereon. The operations include controlling the optical system and the light source and detector on the optical system, analyzing the light detected by the detector, generating and / or controlling the generation of a reference pattern in a reference pattern module, and controlling the movement of a stage carrying a substrate and the movement of the reference pattern module to combine the overlay measurement pattern from the substrate on the stage with the diffracted light of the reference pattern from the reference pattern module. Therefore, in some embodiments, the computer system 1000 provides the functions of an analyzer module 830, a main controller 840, a stage controller 802, a layout position controller 806, and a controller of the optical system 804. Fig. 10A In the embodiment, the computer system 1000 provided has a computer 1001, which includes a CD-ROM (eg, CD-ROM or DVD-ROM) drive 1005 and a disk drive 1006, a keyboard 1002, a mouse 1003, and a display 1004.

[0191] Fig. 10B 1 is a schematic diagram showing the internal configuration of the computer system 1000. Fig. 10B In addition to the CD-ROM drive 1005 and the disk drive 1006, the provided computer 1001 also has one or more processors 1011 (e.g., microprocessor unit (MPU)), a ROM 1012 having a program storing a boot program, a random access memory (RAM) 1013 connected to the processor 1011 and temporarily storing application program commands therein and providing a temporary storage area, a hard disk 1014 storing application programs, system programs and data therein, and a bus 1015 connecting the processor 1011, the ROM 1012, etc. It should be noted that the computer system includes a network card (not shown) for providing a connection to a local area network (LAN).

[0192] In the aforementioned embodiment, the program for causing the computer system 1000 to execute the process for determining the overlay error of the semiconductor device may be stored in the optical disk 1021 or the magnetic disk 1022 inserted into the optical disk read-only memory drive 1005 or the magnetic disk drive 1014 and transferred to the hard disk 1014. Alternatively, the program may be transferred to the computer 1001 via a network (not shown) and stored in the hard disk 1014. When executed, the program is loaded into the RAM 1013. The program may be loaded from the optical disk 1021 or the magnetic disk 1022 or directly from the network. The program does not necessarily have to include, for example, an operating system (OS) or a third-party program to cause the computer 1001 to execute the process for manufacturing the lithography mask of the semiconductor device in the aforementioned embodiment. The program may only include a command portion to call the appropriate function (module) in a controlled mode and obtain the desired result.

[0193] As described above, an independent reference pattern module separated from the substrate can be used to determine the overlay error between different layout patterns of the substrate, or to determine the overlay error between an existing layout pattern on the substrate and a layout pattern of a photoresist material layer patterned by a lithography process on the substrate. By using an independent reference pattern module, the overlay error of each thin layer can be measured relative to the independent reference pattern module. The overlay error of each two thin layers can be determined by the algebraic sum of the overlay errors between the two thin layers and the independent reference pattern module. Therefore, for different patterned thin layers of the substrate, it is not necessary to have multiple overlay measurement patterns in each thin layer to ensure that there is overlap between the overlay measurement patterns of each two thin layers. In addition, when the thin film stack changes, it is not necessary to redesign the overlay measurement pattern.

[0194] It should be understood that not all advantages are necessarily discussed herein, not all embodiments or examples require a particular advantage, and other embodiments or examples may provide different advantages.

[0195] According to some embodiments of the present disclosure, a method for measuring overlay error is provided. The method includes setting a reference pattern module above a substrate. The substrate includes a first overlay measurement pattern located at a first position, and a second overlay measurement pattern located at a second position and separated from the first overlay measurement pattern. The reference pattern module includes a first reference pattern and a second reference pattern separated from the first reference pattern. The method includes at least creating a first reference pattern overlapping with a first portion of the first overlay measurement pattern below the reference pattern module, and while creating the first portion of the overlap, at least creating a second reference pattern overlapping with a second portion of the second overlay measurement pattern below the reference pattern module. The method also includes determining a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, determining a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate, and determining an overall overlay error between the first overlay measurement pattern and the second overlay measurement pattern of the substrate based on the first overlay error and the second overlay error.

[0196] In one embodiment, the first overlay measurement pattern is included in a first layout pattern located in a first thin layer of the substrate, and the second overlay measurement pattern is included in a second layout pattern located in a second thin layer of the substrate different from the first thin layer, and the overlay error between the first layout pattern and the second layout pattern is determined based on the overall overlay error.

[0197] In one embodiment, determining the overlay error between the first layout pattern and the second layout pattern includes determining an algebraic sum of the first overlay error and the second overlay error.

[0198] In one embodiment, determining the first overlay error includes applying a first light beam to a first portion of the first reference pattern and the first overlay measurement pattern overlapped with each other, and analyzing diffracted light from the first overlay measurement pattern and the first reference pattern to determine the first overlay error.

[0199] In one embodiment, determining the second overlay error includes applying a second light beam to a second portion of the second reference pattern and the second overlay measurement pattern overlapped with each other, and analyzing diffracted light from the second overlay measurement pattern and the second reference pattern to determine the second overlay error.

[0200] In one embodiment, the analysis of the diffracted light includes determining the intensity difference between the positive first-order diffracted light and the negative first-order diffracted light.

[0201] In one embodiment, the method further comprises generating a first reference pattern and a second reference pattern of a reference pattern module before creating the first partial overlap, wherein the first reference pattern has a first pitch equal to the pitch of the first overlay measurement pattern of the substrate, and the second reference pattern has a second pitch equal to the pitch of the second overlay measurement pattern of the substrate.

[0202] In one embodiment, the first reference pattern of the reference pattern module includes a first group of multiple third patterns, the first group of multiple third patterns extending in the first direction and arranged in a second direction intersecting the first direction, and a second group of multiple third patterns extending in the first direction and arranged in the second direction. The first group of multiple third patterns and the second group of multiple third patterns are arranged at equal distances D3 on both sides of a third center line extending along the first direction. In addition, the first overlay measurement pattern of the substrate includes a third group of multiple first patterns, the third group of multiple first patterns extending in the first direction and arranged in a second direction intersecting the first direction, and a fourth group of multiple first patterns extending in the first direction and arranged in the second direction. The third group of multiple first patterns and the fourth group of multiple first patterns are arranged at an equal distance D1 on both sides of the first center line extending along the first direction, and when the first reference pattern of the reference pattern module is arranged above the first overlay measurement pattern of the above-mentioned substrate and the first center line overlaps with the third center line, the first group of multiple third patterns of the first reference pattern of the reference pattern module and the third group of multiple first patterns of the first overlay measurement pattern of the above-mentioned substrate have a first offset d=D1-D3, and the second group of multiple third patterns of the first reference pattern of the reference pattern module and the fourth group of multiple first patterns of the first overlay measurement pattern of the above-mentioned substrate have a second offset -d=D3-D1.

[0203] In one embodiment, the determination of the first overlay error includes applying a first light beam to a first portion of the first overlay measurement pattern overlapping the first reference pattern. The determination of the first overlay error also includes analyzing first diffraction light from a first set of multiple third patterns of the first reference pattern and a third set of multiple first patterns of the first overlay measurement pattern, so as to determine a first asymmetric function AS1 based on positive first-order diffraction and negative first-order diffraction of the first diffraction light. The determination of the first overlay error also includes analyzing second diffraction light from a second set of multiple third patterns of the first reference pattern and a fourth set of multiple first patterns of the first overlay measurement pattern, so as to determine a second asymmetric function AS2 based on positive first-order diffraction and negative first-order diffraction of the second diffraction light. The determination of the first overlay error also includes determining a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate as:

[0204]

[0205] According to some embodiments of the present disclosure, a method for measuring overlay error is provided. The method includes performing a first analysis on a first diffraction light combination of a first reference pattern received from a reference pattern module and a first overlay measurement pattern received from a first position of a first thin layer of a substrate to determine a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate. The method also includes performing a second analysis on a second diffraction light combination of a second reference pattern received from the reference pattern module and a second overlay measurement pattern received from a second position of a second thin layer of the substrate to determine a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate. The method also includes determining an overall overlay error between the first overlay measurement pattern and the second overlay measurement pattern based on the first overlay error and the second overlay error.

[0206] In one embodiment, the reference pattern module is disposed in parallel above the substrate.

[0207] In one embodiment, the first overlay measurement pattern and the second overlay measurement pattern are located in different thin layers of the substrate.

[0208] In one embodiment, the reference pattern module is arranged to be perpendicular to the substrate, and the method further comprises projecting the coherent light beam onto a beam splitter, and configuring the beam splitter to guide the first portion of the coherent light beam from the beam splitter to the first reference pattern of the reference pattern module, and to guide the remaining second portion of the coherent light beam from the beam splitter to the first position of the first thin layer of the substrate. The method further comprises combining the diffraction light of the first reference pattern received from the reference pattern module and the first overlay measurement pattern received from the first position of the substrate through the beam splitter to generate a first diffraction light combination. The method further comprises guiding the first diffraction light combination received from the first overlay measurement pattern and the first reference pattern received to an optical system through the beam splitter, wherein the optical system is used for detection and analysis. The method further comprises analyzing the positive first-order diffraction and the negative first-order diffraction of the first diffraction light combination to determine the first overlay error through an analyzer module coupled to or included in the optical system.

[0209] In one embodiment, the method further comprises configuring the beam splitter to direct the first portion of the coherent light beam from the beam splitter to the second reference pattern of the reference pattern module, and directing the remaining second portion of the coherent light beam from the beam splitter to the second position of the second thin layer of the substrate. The method comprises combining the diffracted light received from the second reference pattern of the reference pattern module and the diffracted light received from the second position of the substrate through the beam splitter to generate a second diffracted light combination. The method comprises directing the second diffracted light combination received from the second overlay measurement pattern and the second reference pattern to an optical system through the beam splitter, wherein the optical system is used for detection and analysis. The method further comprises analyzing the positive first-order diffraction and the negative first-order diffraction of the second diffracted light combination through the analyzer module to determine the second overlay error.

[0210] According to some embodiments of the present disclosure, a system for determining an overlay error is provided. The system includes a main controller and a reference pattern module disposed above a substrate, the substrate including a first overlay measurement pattern located in a first position of the substrate, and a second overlay measurement pattern located in a second position of the substrate. The system includes an analyzer module coupled to the main controller. The analyzer module receives a first reference pattern and a second reference pattern. The system includes a layout generator coupled to the main controller, and is configured to receive the first reference pattern and the second reference pattern from the analyzer module via the main controller, and receive an offset between the first reference pattern and the second reference pattern. The layout generator is also coupled to the reference pattern module, and generates the first reference pattern and the second reference pattern in the reference pattern module. The system includes a stage controller coupled to the main controller to control the movement of the substrate, and includes an optical system, the optical system including one or more light sources and coupled to the main controller. The one or more light sources generate a first light beam to illuminate the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate. The one or more light sources generate a second light beam to illuminate the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate. The optical system also includes one or more light detectors, and the one or more light detectors receive a first diffraction light combination from the first overlay measurement pattern and the first reference pattern, and receive a second diffraction light combination from the second overlay measurement pattern and the second reference pattern. The analyzer module also receives a detection signal related to the first diffraction light combination to determine a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, and receives a detection signal related to the second diffraction light combination to determine a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate.

[0211] In one embodiment, the first overlay measurement pattern is included in a first layout pattern in a first thin layer of the substrate, and the second overlay measurement pattern is included in a second layout pattern in a second thin layer of the substrate different from the first thin layer. An overlay error between the first layout pattern and the second layout pattern of the substrate is determined based on the first overlay error and the second overlay error.

[0212] In one embodiment, the reference pattern module is arranged parallel to the substrate. The system further comprises a layout position controller coupled to the reference pattern module so as to move the reference pattern module parallel to the substrate. The stage controller and the layout position controller at least generate a first reference pattern above the substrate and a first partial overlap of the first overlay measurement pattern in the first position of the substrate. And also generate at least a second reference pattern above the substrate and a second partial overlap of the second overlay measurement pattern in the second position of the substrate. The one or more light sources generate a first light beam above the first partial overlap and a second light beam above the second partial overlap.

[0213] In one embodiment, the reference pattern module is disposed above the substrate and perpendicular to the surface of the substrate. The system further comprises a layout position controller coupled to the reference pattern module to move the reference pattern module perpendicular to the substrate. The system comprises a spectroscope to receive a first light beam and split the first light beam so that a first portion of the first light beam illuminates a first overlay measurement pattern at a first position of the substrate, and a remaining second portion of the first light beam illuminates a first reference pattern of the reference pattern module. The spectroscope also receives a second light beam and splits the second light beam so that a first portion of the second light beam illuminates a second overlay measurement pattern at a second position of the substrate, and a remaining second portion of the second light beam illuminates a second reference pattern of the reference pattern module. The stage controller and the layout position controller move the substrate and the reference pattern module so that a first portion and a remaining second portion of the first light beam simultaneously illuminate the first overlay measurement pattern and the first reference pattern, and a first portion and a remaining second portion of the second light beam simultaneously illuminate the second overlay measurement pattern and the second reference pattern.

[0214] In one embodiment, the diffracted light from the first reference pattern and the first overlay measurement pattern is reflected from the reference pattern module and the substrate, respectively. The spectroscope combines the diffracted light from the first overlay measurement pattern and the first reference pattern, generates a first diffracted light combination, and transmits the first diffracted light combination to the one or more light detectors of the optical system. The diffracted light from the second reference pattern and the second overlay measurement pattern is reflected from the reference pattern module and the substrate, respectively. The spectroscope also combines the diffracted light from the second overlay measurement pattern and the second reference pattern, generates a second diffracted light combination, and transmits the second diffracted light combination to the one or more light detectors of the optical system.

[0215] In one embodiment, the one or more light sources of the optical system are coherent light sources.

[0216] The foregoing text summarizes the features of multiple embodiments or examples so that those with ordinary knowledge in the art can better understand the aspects of the present disclosure. Those with ordinary knowledge in the art should understand that they can easily design or modify other processes and structures based on the present disclosure to accomplish the same purpose and / or achieve the same advantages as the embodiments or examples introduced herein. Those with ordinary knowledge in the art should also understand that these equivalent structures do not depart from the spirit and scope of the present disclosure, and various changes, substitutions and modifications can be made to the present disclosure without departing from the spirit and scope of the present disclosure.

Claims

1. A method for determining an overlay error, comprising: A reference pattern module is disposed above a substrate in a manner separated from the substrate, the substrate comprising a first overlay measurement pattern located at a first position, and a second overlay measurement pattern located at a second position and separated from the first overlay measurement pattern, wherein the reference pattern module comprises a first reference pattern and a second reference pattern separated from the first reference pattern; At least creating a first reference pattern that overlaps a first portion of the first overlay measurement pattern below the reference pattern module; While creating the first partial overlap, at least create a second partial overlap between the second reference pattern and the second overlay measurement pattern below the reference pattern module; determining a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate; determining a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate; and An overall overlay error between the first overlay measurement pattern and the second overlay measurement pattern of the substrate is determined based on the first overlay error and the second overlay error.

2. The method for determining overlay error according to claim 1, wherein: The first overlay measurement pattern is included in a first layout pattern located in a first thin layer of the substrate, and the second overlay measurement pattern is included in a second layout pattern located in a second thin layer of the substrate different from the first thin layer, and an overlay error between the first layout pattern and the second layout pattern is determined based on the overall overlay error.

3. The method for determining overlay error according to claim 2, wherein: The determination of the overlay error between the first layout pattern and the second layout pattern includes determining an algebraic sum of the first overlay error and the second overlay error.

4. The method for determining overlay error according to claim 1, wherein: The determination of the first overlay error includes: applying a first light beam to the first portion of the first reference pattern overlapping the first overlay measurement pattern; and The diffracted light from the first overlay measurement pattern and the first reference pattern is analyzed to determine the first overlay error.

5. The method for determining overlay error according to claim 4, wherein: The determination of the second overlay error includes: applying a second light beam to the second portion where the second reference pattern overlaps the second overlay measurement pattern; and The diffracted light from the second overlay measurement pattern and the second reference pattern is analyzed to determine the second overlay error.

6. The method for determining overlay error according to claim 5, wherein: The analysis of the diffracted light includes determining an intensity difference between the positive first-order diffracted light and the negative first-order diffracted light.

7. The method for determining an overlay error according to claim 1, further comprising: Before creating the first partial overlap, the first reference pattern and the second reference pattern of the reference pattern module are generated, wherein the first reference pattern has a first pitch equal to the pitch of the first overlay measurement pattern of the substrate, and the second reference pattern has a second pitch equal to the pitch of the second overlay measurement pattern of the substrate.

8. The method for determining overlay error according to claim 7, wherein: The first reference pattern of the reference pattern module includes a first group of multiple third-time patterns, the first group of multiple third-time patterns extending in a first direction and arranged in a second direction intersecting the first direction, and a second group of multiple third-time patterns extending in the first direction and arranged in the second direction, wherein the first group of multiple third-time patterns and the second group of multiple third-time patterns are arranged at an equal distance D3 on both sides of a third center line extending along the first direction; The first overlay measurement pattern of the substrate includes a third group of multiple first time patterns, which extend in the first direction and are arranged in the second direction intersecting the first direction, and a fourth group of multiple first time patterns, which extend in the first direction and are arranged in the second direction, wherein the third group of multiple first time patterns and the fourth group of multiple first time patterns are arranged at an equal distance D1 on both sides of a first center line extending along the first direction, wherein when the first reference pattern of the reference pattern module is arranged above the first overlay measurement pattern of the substrate and the first center line overlaps with the third center line, the first group of multiple third time patterns of the first reference pattern of the reference pattern module and the third group of multiple first time patterns of the first overlay measurement pattern of the substrate have a first offset d=D1-D3, and the second group of multiple third time patterns of the first reference pattern of the reference pattern module and the fourth group of multiple first time patterns of the first overlay measurement pattern of the substrate have a second offset -d=D3-D1.

9. The method for determining overlay error according to claim 8, wherein: The determination of the first overlay error includes: Applying a first light beam to the first portion of the first overlay measurement pattern overlapping the first reference pattern; Analyze a first diffraction light from the first plurality of third-order patterns of the first reference pattern and the third plurality of first-order patterns of the first overlay measurement pattern to determine a first asymmetric function AS1 based on a positive first-order diffraction and a negative first-order diffraction of the first diffraction light; Analyzing a second diffraction light from the second plurality of third patterns of the first reference pattern and the fourth plurality of first patterns of the first overlay measurement pattern to determine a second asymmetric function AS2 based on a positive first-order diffraction and a negative first-order diffraction of the second diffraction light; and The first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate is determined as:

10. A method for determining an overlay error, comprising: performing a first analysis on a first diffraction light combination of a first reference pattern received from a reference pattern module and a first overlay measurement pattern received from a first position of a first thin layer of a substrate to determine a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, wherein the reference pattern module is separately disposed above the substrate; performing a second analysis on a second diffraction light combination of a second reference pattern received from the reference pattern module and a second overlay measurement pattern received from a second position of a second thin layer of the substrate to determine a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate; and An overall overlay error between the first overlay measurement pattern and the second overlay measurement pattern of the substrate is determined based on the first overlay error and the second overlay error.

11. The method for determining overlay error according to claim 10, wherein: The reference pattern module is arranged in parallel above the substrate.

12. The method for determining overlay error according to claim 10, wherein: The first overlay measurement pattern and the second overlay measurement pattern are located in different thin layers of the substrate.

13. The method for determining overlay error according to claim 10, wherein: The reference pattern module is arranged to be perpendicular to the substrate, and the method for determining the overlay error further comprises: Projecting a co-tuned light beam onto a beam splitter; The beam splitter is configured to guide a first portion of the coherent light beam from the beam splitter to the first reference pattern of the reference pattern module, and to guide a remaining second portion of the coherent light beam from the beam splitter to the first position of the first thin layer of the substrate; Combining the first reference pattern received from the reference pattern module and the diffracted light of the first overlay measurement pattern received from the first position of the substrate through the beam splitter to generate the first diffracted light combination; guiding the first diffraction light combination received from the first overlay measurement pattern and the first reference pattern to an optical system through the beam splitter, wherein the optical system is used for detection and analysis; and The positive first-order diffraction and the negative first-order diffraction of the first diffraction light combination are analyzed by an analyzer module coupled to the optical system or included in the optical system to determine the first overlay error.

14. The method for determining an overlay error according to claim 13, further comprising: The beam splitter is configured to guide the first portion of the coherent light beam from the beam splitter to the second reference pattern of the reference pattern module, and to guide the remaining second portion of the coherent light beam from the beam splitter to the second position of the second thin layer of the substrate; Combining the second reference pattern received from the reference pattern module and the diffracted light of the second overlay measurement pattern received from the second position of the substrate through the beam splitter to generate the second diffracted light combination; guiding the second diffraction light combination received from the second overlay measurement pattern and the second reference pattern to the optical system through the beam splitter, wherein the optical system is used for detection and analysis; and The positive first-order diffraction and the negative first-order diffraction of the second diffraction light combination are analyzed by the analyzer module to determine the second overlay error.

15. A system for determining an overlay error, comprising: a main controller; a reference pattern module disposed above a substrate in a separate manner, the substrate including a first overlay measurement pattern located in a first position of the substrate and a second overlay measurement pattern located in a second position of the substrate; an analyzer module coupled to the main controller, wherein the analyzer module is configured to receive a first reference pattern and a second reference pattern; a layout generator coupled to the main controller and configured to receive the first reference pattern and the second reference pattern from the analyzer module via the main controller, and receive an offset between the first reference pattern and the second reference pattern, the layout generator is also coupled to the reference pattern module and configured to generate the first reference pattern and the second reference pattern in the reference pattern module; a stage controller coupled to the main controller and configured to control the movement of the substrate; and an optical system comprising one or more light sources and coupled to the main controller, wherein the one or more light sources are configured to generate a first light beam to illuminate the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, and to generate a second light beam to illuminate the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate; The optical system further includes one or more photodetectors configured to receive a first diffraction light combination from the first overlay measurement pattern and the first reference pattern, and to receive a second diffraction light combination from the second overlay measurement pattern and the second reference pattern; and The analyzer module is further configured to receive a detection signal associated with the first diffraction light combination to determine a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate, and to receive a detection signal associated with the second diffraction light combination to determine a second overlay error between the second reference pattern of the reference pattern module and the second overlay measurement pattern of the substrate.

16. The system for determining overlay error according to claim 15, wherein: The first overlay measurement pattern is included in a first layout pattern in a first thin layer of the substrate, and the second overlay measurement pattern is included in a second layout pattern in a second thin layer of the substrate different from the first thin layer, and an overlay error between the first layout pattern and the second layout pattern of the substrate is determined based on the first overlay error and the second overlay error.

17. The system for determining overlay error according to claim 15, wherein: The reference pattern module is arranged in parallel above the substrate, wherein the system for determining the overlay error further comprises a layout position controller, which is coupled to the reference pattern module and configured to move the reference pattern module parallel to the substrate, wherein the stage controller and the layout position controller are configured to at least generate a first partial overlap between the first reference pattern above the substrate and the first overlay measurement pattern in the first position of the substrate, and to generate at least a second partial overlap between the second reference pattern above the substrate and the second overlay measurement pattern in the second position of the substrate, and wherein the one or more light sources are configured to generate the first light beam above the first partial overlap and generate the second light beam above the second partial overlap.

18. The system for determining overlay error according to claim 15, wherein: The reference pattern module is disposed above the substrate and perpendicular to the surface of the substrate, wherein the system for determining the overlay error further comprises: a layout position controller coupled to the reference pattern module and configured to move the reference pattern module perpendicular to the substrate; and a beam splitter configured to receive the first light beam and split the first light beam so that a first portion of the first light beam illuminates the first overlay measurement pattern at the first position of the substrate, and a remaining second portion of the first light beam illuminates the first reference pattern of the reference pattern module; The beam splitter is further configured to receive the second light beam and split the second light beam so that a first portion of the second light beam illuminates the second overlay measurement pattern at the second position of the substrate, and a remaining second portion of the second light beam illuminates the second reference pattern of the reference pattern module; The stage controller and the layout position controller are configured to move the substrate and the reference pattern module so that the first portion and the remaining second portion of the first light beam simultaneously illuminate the first overlay measurement pattern and the first reference pattern, and the first portion and the remaining second portion of the second light beam simultaneously illuminate the second overlay measurement pattern and the second reference pattern.

19. The system for determining overlay error according to claim 18, wherein: The diffracted light from the first reference pattern and the first overlay measurement pattern is reflected from the reference pattern module and the substrate respectively, and the beam splitter is configured to combine the diffracted light from the first overlay measurement pattern and the first reference pattern to generate the first diffracted light combination and transmit the first diffracted light combination to the one or more light detectors of the optical system; and The diffracted light from the second reference pattern and the second overlay measurement pattern is reflected from the reference pattern module and the substrate respectively, and the spectroscope is configured to combine the diffracted light from the second overlay measurement pattern and the second reference pattern to generate the second diffracted light combination and transmit the second diffracted light combination to the one or more light detectors of the optical system.

20. The system for determining overlay error according to claim 15, wherein: The one or more light sources of the optical system are coherent light sources.

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