Method and apparatus for correcting overlay error, method and apparatus for detecting alignment of wafer

Abstract

The disclosure provides a method and device for correcting overlay error, and a method and device for detecting alignment of a wafer. After a machine determines a first overlay error value between a first alignment mark of a wafer to be detected layer and a second alignment mark of a target layer, the first overlay error value obtained by measurement is corrected based on a measurement error parameter to obtain a more accurate second overlay error value. Due to the correction of the measurement error parameter, the error caused by the asymmetry or defects of the first alignment mark in the second overlay error value is eliminated, the accuracy of the overlay error value obtained by the machine is improved, and the machine can perform alignment detection and other processes according to the accurate overlay error value.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor technology, and particularly relates to a method and device for correcting overlay error, and a method and device for detecting alignment of wafer. BACKGROUND

[0002] In the production and processing of a wafer, it is necessary to determine whether a to-be-detected layer currently being processed is aligned with a target layer, so as to ensure the effectiveness of the production and processing of the to-be-detected layer. For example, an overlay error value between a plurality of alignment marks of the to-be-detected layer and a plurality of alignment marks of the target layer can be obtained by optical signal measurement, and then M3S, Res and other overlay error parameters can be calculated according to the overlay error values between all the alignment marks, and finally it is determined whether the to-be-detected layer is aligned with the target layer according to the overlay error.

[0003] However, when the to-be-detected layer of the wafer has asymmetry or defects in the alignment marks due to manufacturing processes and the like, the measured overlay error will be inaccurate, and thus it is impossible to accurately determine whether the to-be-detected layer of the wafer is aligned with the target layer according to the overlay error. Therefore, how to improve the accuracy of the measured overlay error is a technical problem to be solved in the field. SUMMARY

[0004] The present disclosure provides a method and device for correcting overlay error, and a method and device for detecting alignment of wafer, for improving the accuracy of the measured overlay error.

[0005] The first aspect of the present disclosure provides a method for correcting overlay error, comprising: obtaining a first overlay error value of a first alignment mark of a to-be-detected layer of a wafer relative to a second alignment mark of a target layer; correcting the first overlay error value according to a measurement error parameter corresponding to the to-be-detected layer to obtain a second overlay error value; the measurement error parameter is used to indicate the influence of the asymmetry or defects of the first alignment mark on the first overlay error value.

[0006] In an embodiment of the first aspect of the present disclosure, the measurement error parameter is related to a measurement quality parameter, a first parameter and a second parameter of the to-be-detected layer; the measurement quality parameter is the difference between the first derivative midpoint of the first alignment mark and the first midpoint of the first alignment mark when the first midpoint of the first alignment mark is measured; the first parameter is used to indicate the relationship between the measurement quality parameter and the first overlay error value; and the second parameter is used to indicate the influence of the measurement quality parameter on the first overlay error value measured by the to-be-detected layer.

[0007] In an embodiment of the first aspect of the present disclosure, the method further comprises: obtaining the measurement error parameter; or determining the measurement quality parameter, the first parameter and the second parameter, determining the measurement error parameter according to the measurement quality parameter, the first parameter and the second parameter, and the measurement error parameter being the product of the measurement quality parameter, the first parameter and the second parameter.

[0008] In an embodiment of the first aspect of the present disclosure, the method for determining the first parameter comprises: obtaining overlay error value training data of a layer to be detected; obtaining measurement quality parameter training data of the layer to be detected; and fitting the first parameter according to the overlay error value training data and the measurement quality parameter training data.

[0009] In an embodiment of the first aspect of the present disclosure, the first overlay error value of the first alignment mark of the layer to be detected relative to the second alignment mark of the target layer is obtained by: determining a first midpoint of the first alignment mark according to an optical signal of the first alignment mark; determining a second midpoint of the second alignment mark according to an optical signal of the second alignment mark; and obtaining the first overlay error value according to a difference between the first midpoint and the second midpoint.

[0010] In an embodiment of the first aspect of the present disclosure, the first overlay error value is corrected according to a measurement error parameter corresponding to the layer to be detected to obtain a second overlay error value, comprising: obtaining the second overlay error value according to a difference between the first overlay error value and the measurement error parameter.

[0011] In an embodiment of the first aspect of the present disclosure, after obtaining the second overlay error value, the method further comprises: outputting the second overlay error value and / or a parameter corresponding to the second overlay error value.

[0012] The second aspect of the present disclosure provides a wafer alignment detection method, comprising: determining a plurality of second overlay error values corresponding to a plurality of first alignment marks of a layer to be detected of a wafer; the second overlay error value is obtained according to the method of any one of the first aspect of the present disclosure; and determining whether the layer to be detected is aligned with a target layer according to the plurality of second overlay error values.

[0013] The third aspect of the present disclosure provides an overlay error correction device, comprising: an obtaining module configured to obtain a first overlay error value of a first alignment mark of a layer to be detected relative to a second alignment mark of a target layer; and a correction module configured to correct the first overlay error value according to a measurement error parameter corresponding to the layer to be detected to obtain a second overlay error value; the measurement error parameter is used to indicate an influence of asymmetry or defects of the first alignment mark on the first overlay error value.

[0014] In an embodiment of the third aspect of the present disclosure, the measurement error parameter is related to a measurement quality parameter of the layer to be detected, a first parameter and a second parameter; the measurement quality parameter is a difference between a first derivative midpoint of the first alignment mark and a first midpoint of the first alignment mark when the first midpoint of the first alignment mark is measured; the first parameter is used to indicate a relationship between the measurement quality parameter and the first overlay error value; and the second parameter is used to indicate an influence of the measurement quality parameter on the first overlay error value obtained by measuring the layer to be detected.

[0015] In an embodiment of the third aspect of the present disclosure, the obtaining module is further configured to obtain a measurement error parameter; or, the apparatus further comprises a determining module configured to determine the measurement quality parameter, the first parameter and the second parameter, and determine the measurement error parameter according to the measurement quality parameter, the first parameter and the second parameter, wherein the measurement error parameter is a product of the measurement quality parameter, the first parameter and the second parameter.

[0016] In an embodiment of the third aspect of the present disclosure, the determining module is specifically configured to obtain overlay error value training data of the layer to be detected, obtain measurement quality parameter training data of the layer to be detected, and fit the first parameter according to the overlay error value training data and the measurement quality parameter training data.

[0017] In an embodiment of the third aspect of the present disclosure, the obtaining module is configured to determine a first midpoint of the first alignment mark according to an optical signal of the first alignment mark, determine a second midpoint of the second alignment mark according to an optical signal of the second alignment mark, and obtain the first overlay error value according to a difference between the first midpoint and the second midpoint.

[0018] In an embodiment of the third aspect of the present disclosure, the correcting module is configured to obtain the second overlay error value according to a difference between the first overlay error value and the measurement error parameter.

[0019] In an embodiment of the third aspect of the present disclosure, the apparatus further comprises an output module configured to output the second overlay error value and / or a parameter corresponding to the second overlay error value.

[0020] The fourth aspect of the present disclosure provides an alignment detection apparatus for a wafer, comprising: a determining module configured to determine a plurality of second overlay error values corresponding to a plurality of first alignment marks of a layer to be detected of the wafer; the second overlay error value is obtained according to the method of any one of the first aspect of the present disclosure; and a detection module configured to determine whether the layer to be detected is aligned with a target layer according to the plurality of second overlay error values.

[0021] In summary, the overlay error correction method and apparatus, and the alignment detection method and apparatus for a wafer provided by the present disclosure can correct the first overlay error value obtained by measurement based on a measurement error parameter after a machine determines the first overlay error value between the first alignment mark of the layer to be detected of the wafer and the second alignment mark of the target layer, so as to obtain a more accurate second overlay error value. Since the correction based on the measurement error parameter eliminates the error in the second overlay error value caused by the asymmetry or defects of the first alignment mark, the accuracy of the overlay error value obtained by the machine is improved, and thus the machine can perform alignment detection and other processes according to the accurate overlay error value. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A schematic diagram of the alignment mark provided on the wafer of the present disclosure;

[0023] Figure 2 A structural schematic diagram of alignment marks of a wafer provided by the present disclosure in a y direction;

[0024] Figure 3 A structural schematic diagram of alignment marks of a wafer provided by the present disclosure in a z direction;

[0025] Figure 4 A schematic diagram of determining a midpoint of an alignment mark provided by the present disclosure;

[0026] Figure 5 A schematic diagram of a first overlay error value of a layer to be detected of a wafer provided by the present disclosure;

[0027] Figure 6 A schematic diagram of an alignment mark provided by the present disclosure with asymmetry;

[0028] Figure 7 A flowchart of an embodiment of a correction method of an overlay error provided by the present disclosure;

[0029] Figure 8 A schematic diagram of measuring a quality parameter provided by the present disclosure;

[0030] Figure 9 A schematic diagram of a corresponding relationship between a quality parameter and a first overlay error value provided by the present disclosure;

[0031] Figure 10 A flowchart of an embodiment of an alignment detection method of a wafer provided by the present disclosure. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present disclosure. In addition, although the disclosure is introduced according to one or more exemplary examples, it should be understood that each aspect of these disclosures can also constitute a complete embodiment independently.

[0033] It should be noted that the brief description of the terms in the present disclosure is only for the convenience of understanding the subsequently described embodiments, and is not intended to limit the embodiments of the present disclosure. Unless otherwise specified, these terms should be understood according to their ordinary and general meanings.

[0034] The terms "first", "second", and the like in the specification and claims of the present disclosure and above-described drawings are used to distinguish similar or like objects or entities, and do not necessarily mean a specific order or sequence unless otherwise noted. It should be understood that the terms used in this way can be interchanged as appropriate, for example, those other than the order given can be implemented according to the embodiment illustration or description of the present disclosure.

[0035] In addition, the terms "comprising" and "having" and any variations thereof are intended to cover, but not exclusively, inclusion, for example, a product or device including a series of components does not have to be limited to those components clearly listed, but can include other components not clearly listed or inherent to these products or devices.

[0036] During the production and processing of the wafer, the machine can form a preset circuit pattern on each layer of the wafer through lithography and the like. In order to ensure the accuracy and effectiveness of the circuit pattern of each layer, the machine also needs to detect whether the layer being processed is aligned before processing the layer. For example, the machine can record a layer that has been determined to be aligned as a target layer, and then measure the overlay error (Overlay, referred to as: OVL) value between the multiple alignment marks of the current layer to be detected and the multiple alignment marks of the target layer through optical signals, and then calculate the M3S, Res and other overlay error parameters according to all overlay error values between all alignment marks on the layer to be detected and the corresponding alignment marks on the target layer, and finally determine whether the layer to be detected is aligned with the target layer according to the overlay error. This measurement method can also be referred to as IBO (image based Overlay).

[0037] For example, Figure 1 A schematic diagram of the setting of the alignment marks on the wafer provided by the present disclosure is shown. As Figure 1 shown, taking the layer 10 of the wafer being processed by the machine as an example, multiple repeated exposure units 101 are provided on the layer 10 to be detected. Multiple alignment marks 1011 are provided at the same position in each exposure unit 101, and the alignment marks 1011 are provided at the same position of the vertices, edge midpoints and the like of the multiple alignment marks 1011 in each exposure unit 101.

[0038] Specifically, Figure 2 A schematic diagram of the structure of the alignment marks of the wafer in the y direction provided by the present disclosure is shown. Figure 3 A schematic diagram of the structure of the alignment marks of the wafer in the z direction provided by the present disclosure is shown. As Figure 2 and Figure 3As shown, the first alignment mark 1011 on the wafer layer to be detected 10 is taken as an example, and the second alignment mark 2011 corresponding to the first alignment mark 1011 is arranged on the target layer 20 of the wafer. In an embodiment, the machine can determine whether the wafer layer to be detected 10 is aligned with the target layer 20 by a plurality of overlay (OVL) values between the plurality of first alignment marks 1011 on the wafer layer to be detected 10 and the plurality of second alignment marks 2011 on the target layer.

[0039] Figure 2 and Figure 3 For example, the first alignment mark 1011 and the second alignment mark 2011 are rectangular, and the machine can determine the overlay value between the first alignment mark 1011 and the second alignment mark 2011 by the distance between the first midpoint of the first alignment mark 1011 and the second midpoint of the second alignment mark 2011.

[0040] Figure 4 A schematic diagram for determining the midpoint of the alignment mark is provided in the present disclosure. In an embodiment, as shown in Figure 4 In order to obtain the first midpoint of the first alignment mark 1011, the machine measures the optical signals corresponding to the edges a and b of the first alignment mark 1011 parallel to the y direction in the x direction, and determines the median value X1 of the first alignment mark 1011 in the x direction according to the changes of the optical signals of the edges a and b. Correspondingly, the machine can also measure the optical signals corresponding to the edges of the first alignment mark perpendicular to the x direction in the y direction, and determine the median value Y1 of the first alignment mark 1011 in the y direction. Thus, the first midpoint of the first alignment mark 1011 is recorded as (X1, Y1). Similarly, the machine can determine the median value X2 of the second alignment mark 2011 in the x direction according to the changes of the optical signals between the two edges of the second alignment mark 2011 parallel to the y direction in the x direction, and determine the median value Y2 of the second alignment mark 2011 in the y direction according to the changes of the optical signals between the two edges of the second alignment mark 2011 parallel to the x direction in the y direction, so as to record the midpoint of the second alignment mark 2011 as (X2, Y2). Finally, the machine can determine the first overlay value of the first alignment mark 1011 and the second alignment mark 2011 according to the difference between the first midpoint (X1, Y1) of the first alignment mark 1011 and the midpoint (X2, Y2) of the second alignment mark 2011, and the first overlay value can be represented as a vector in the x-y plane. The optical signal can be an optical waveform.

[0041] Figure 5 A schematic diagram of the first overlay value of the wafer layer to be detected is provided in the present disclosure. As shown in Figure 5 The machine can determine the first overlay value of the wafer layer to be detected according to Figure 4In the same way that the first overlay error value between the first alignment mark 1011 and the second alignment mark 2011 is obtained, the overlay error values corresponding to all the alignment mark pairs on the wafer layer to be detected 10 are determined, and are represented in the form of vectors on the x-y plane.

[0042] However, due to the influence of wafer manufacturing process and other factors, the alignment marks arranged on the wafer surface may have asymmetry or imperfections. For example, Figure 6 A schematic diagram of an alignment mark with asymmetry is provided for the present disclosure. It is assumed that Figure 2 and Figure 3 The first alignment mark 1011 provided in the above is ideal, Figure 6 The first alignment mark 1011 provided in the above is actual. As shown in Figure 6 For the first alignment mark 1011 on the wafer layer to be detected 10, the cross section of the first alignment mark 1011 in the x direction can be seen that the edge a of the actual first alignment mark 1011 is not a rectangular shape, but a left-right asymmetric shape. This results in that when the first overlay error value between the first alignment mark 1011 and the second alignment mark 2011 is measured by the machine, the first overlay error value obtained includes the error caused by the asymmetry of the first alignment mark 1011. When the value of the first overlay error is inaccurate, the machine cannot further determine whether the wafer layer to be detected 10 is aligned with the target layer 20 according to the inaccurate first overlay error value. Therefore, how to improve the accuracy of the measured overlay error is a technical problem to be solved in the art.

[0043] The present disclosure provides an overlay error correction method and a wafer alignment detection method, which can correct the first overlay error value of the wafer layer to be detected by measuring the error parameter, eliminate the influence of the asymmetry or imperfection of the first alignment mark on the first overlay error value, obtain a more accurate second overlay error value, and more accurately determine whether the wafer layer to be detected 10 is aligned with the target layer 20 according to the second overlay error value. The technical solutions of the present disclosure will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0044] Figure 7 A flowchart of an embodiment of the overlay error correction method provided by the present disclosure is shown in Figure 7 The method shown in the above can be executed by a machine for processing wafers, or can also be executed by a computer, a workstation, a server or any electronic device with related data processing capability. In the embodiments of the present disclosure, the execution subject is taken as an example, and is not limited thereto. As shown in Figure 7As shown, the method for correcting overlay error provided by the embodiments of the present disclosure includes:

[0045] S101: The machine obtains a first overlay error value between a first alignment mark 1011 on a to-be-detected layer 10 of a wafer and a second alignment mark 2011 on a target layer 20.

[0046] In an embodiment, the machine can determine a first midpoint of the first alignment mark 1011 according to an optical signal of at least one edge of the first alignment mark 1011, and determine a second midpoint of the second alignment mark 2011 according to an optical signal of at least one edge of the second alignment mark 2011, in the same manner as in the step S101. Figure 4 Then, the machine obtains the first overlay error value according to a difference between the first midpoint and the second midpoint.

[0047] Alternatively, in another embodiment, other electronic devices can be used to determine the first overlay error. Then, in the step S101, the machine can receive the first overlay error sent by the other electronic devices and perform subsequent processing.

[0048] S102: The machine corrects the first overlay error obtained in the step S101 according to a measurement error parameter corresponding to the to-be-detected layer 10 of the wafer, to obtain a second overlay error value after correction.

[0049] Specifically, the measurement error parameter is used to indicate an influence of the first alignment mark 1011 on the structure on the first overlay error obtained in the step S101. For example, Figure 6 As shown, the asymmetry of the edge a of the first alignment mark 1011 causes a difference between the first overlay error value obtained by measurement in the step S101 and an actual overlay error value. The measurement error value is used to indicate the difference. Then, in the step S102, the measurement error parameter is used to correct the first overlay error value, so as to offset the error caused by the asymmetry from the first overlay error value obtained by measurement, to obtain a more accurate second overlay error value.

[0050] It can be understood that, as shown in the steps, Figure 7 as an example, and with reference to Figure 5 When the machine determines a plurality of first alignment marks on the to-be-detected layer 10 of the wafer, the machine can correct the plurality of first alignment marks respectively in the same manner as described above, to obtain a plurality of second alignment marks after correction. The plurality of second alignment marks after correction can be used to jointly detect whether the to-be-detected layer 10 is aligned with the target layer 20.

[0051] In summary, the overlay error correction method provided in this embodiment, after the equipment determines the first overlay error value between the first alignment mark of the layer to be inspected and the second alignment mark of the target layer on the wafer, can correct the measured first overlay error value based on measurement error parameters to obtain a more accurate second overlay error value. In this embodiment, the correction of the first overlay error value by the equipment through measurement error parameters eliminates the error in the second overlay error value caused by the asymmetry or defects of the first alignment mark, thereby improving the accuracy of the overlay error value obtained by the equipment. This ensures that the equipment can subsequently perform alignment inspection and other processing based on the accurate overlay error value.

[0052] In one embodiment, the measurement error parameter is related to the measurement quality parameter Q-merit, the first parameter K1, and the second parameter K2 of the layer 10 to be tested on the wafer. For example, the measurement error parameter can be expressed as the product of the measurement quality parameter Q-merit, the first parameter K1, and the second parameter K2, that is, expressed by the formula: Measurement error parameter = Q-merit * K1 * K2.

[0053] Figure 8 This is a schematic diagram illustrating the measurement quality parameters provided in this disclosure. (Example) Figure 8 As shown, taking edge a of the first alignment mark 1011 as an example. To obtain the measurement quality parameter Q-merit corresponding to edge a, it is possible to... Figure 2 and Figure 3 When measuring the first midpoint, the ideal first alignment mark 1011 is shown. The first derivative of the optical signal of the first edge a in the x-direction of the first alignment mark 1011 is taken, yielding da / dx. Combined with the first derivative db / dx of the second edge b corresponding to the first edge a, the midpoint D1 of the first derivative is obtained. Therefore, the measurement quality parameter Q-merit of the first alignment mark 1011 in the x-direction can be determined by the difference between the midpoint D1 of the first derivative and the first midpoint X1, i.e., Q-merit = OVL' - OVL. Similarly, in machine measurement... Figure 6 When the actual first alignment mark 1011 with asymmetry is at its first midpoint, the actual optical signal of the first edge a in the x-direction is taken as its second derivative da / dx'. Combining this with the first derivative db / dx of the second edge b corresponding to the first edge a, the midpoint D1' of the first derivative is obtained. Then, the measurement quality parameter Q-merit of the first alignment mark 1011 in the x-direction can be determined by the difference between the midpoint D1' of the first derivative and the first midpoint X1'. Figure 8 The figure shows the measurement mass parameter Q-merit in the x-direction. Following the same method described above, the measurement mass parameter Q-merit in the y-direction can also be obtained. From... Figure 8As can be seen from the figure, due to the asymmetry of the actual first alignment mark 1011, there is an error between the measured measurement quality parameter Q-merit of the first alignment mark 1011 and the measurement quality parameter Q-merit of the ideal first alignment mark 1011, and the greater the asymmetry, the greater the measurement quality parameter Q-merit.

[0054] In an embodiment, the first parameter K1 is used to indicate the relationship between the measurement quality parameter and the first overlay error value. In an embodiment, there is a certain corresponding relationship between the actual measured first overlay error value and the measurement quality parameter Q-merit, which can be a negative proportional linear relationship. For example, Figure 9 A corresponding relationship between the measurement quality parameter and the first overlay error value provided by the present disclosure is shown in the figure as Figure 9 Each point in the figure corresponds to an alignment mark on the layer 10 to be detected of the wafer, the horizontal coordinate is the measurement quality parameter corresponding to the alignment mark, and the vertical coordinate is the first overlay error value corresponding to the alignment mark. As can be seen from the line graph, Figure 9 For all alignment marks on the layer 10 to be detected of the wafer, the measurement quality parameter Q-merit and the first overlay error value can be fitted to obtain a linear change relationship: first overlay error = K1*Q-merit+b, thereby obtaining the first parameter K1.

[0055] In an embodiment, the second parameter K2 is used to indicate the influence of the measurement quality parameter on the first overlay error value measured by the layer to be tested. In an embodiment, the second parameter K2 can take a value between 0.8 and 1.2. The second parameter K2 can be preset, can be set in advance, or can be calculated in real time by the machine; it can also be an empirical value, which can be determined according to the type of layer, the type of alignment mark, the type of machine, and the test method. For example, the first overlay error value obtained by measuring in S101 will have an error compared with the ideal overlay error due to various factors. Among them, the contribution of the asymmetry or defects of the first alignment mark to the error can be represented by the second parameter K2. Exemplarily, when K2 is 0.8, it is used to indicate that 80% of the error of the first overlay error value is caused by the asymmetry or defects of the first alignment mark. When K2 is 1, it is used to indicate that all the error of the first overlay error value is caused by the asymmetry or defects of the first alignment mark.

[0056] In an embodiment, the machine as the execution subject can determine the measurement error parameter corresponding to the current layer to be detected before S102. For example, other electronic devices can be used to determine the measurement error parameter according to the measurement quality parameter Q-merit, the first parameter K1 and the second parameter K2, and send it to the machine, and then the machine receives the measurement error parameter sent by the other electronic devices. For another example, the electronic device can determine the measurement quality parameter Q-merit, the first parameter K1 and the second parameter K2, and calculate the measurement error parameter according to the measurement quality parameter Q-merit, the first parameter K1 and the second parameter K2. The measurement quality parameter can be calculated when the machine measures the midpoint of the first alignment mark, and the difference between the first derivative midpoint of the first alignment mark and the first midpoint of the first alignment mark. The first parameter K1 can be calculated in advance by the machine and stored in the storage space, and the machine can obtain the first parameter K1 from the storage space. The second parameter K2 can also be stored in the storage space in advance, and the machine can obtain the second parameter K2 from the storage space.

[0057] In an embodiment, the machine can also calculate the first parameter K1 by fitting. For example, referring to Figure 9 , the machine can obtain the overlay error value training data and the measurement quality parameter training data corresponding to each alignment mark on the layer to be detected as training data, and then perform fitting according to all overlay error training data and measurement quality parameter training data to obtain the first parameter K1. The training data can be the layers to be detected of the same batch of wafers, which can be processed by the same machine, so that the alignment marks on these wafers can have the same asymmetry or defects, and thus the first overlay error value obtained from these alignment marks can be corrected by the measurement error parameter.

[0058] In an embodiment, the machine corrects the first overlay error obtained in S101 according to the measurement error parameter corresponding to the layer to be detected 10 of the wafer in S102 to obtain the corrected second overlay error value, including: the machine obtains the second overlay error value according to the difference between the first overlay error value and the measurement error parameter, for example, the first overlay error value OVL measurement is subtracted from the measurement error parameter Q-merit*K1*K2 to obtain the second overlay error value OVL calibrate :

[0059] OVL calibrate ≈OVL measurement -Q-merit*K1*K2 Formula One

[0060] The derivation process of Formula One is as follows: first, the first overlay error value OVL measurementa difference Inaccuracy between the first overlay error value OVL accurate The difference Inaccuracy can be expressed by Equation Two as follows:

[0061] OVL measurement = OVL accurate + Inaccuracy Equation Two

[0062] According to the fitting result shown in Figure 9 , the difference Inaccuracy can be expressed as a function f(Q-merit) related to the measurement quality parameter Q-merit, and thus Equation Two can be transformed into Equation Three as follows:

[0063] OVL measurement = OVL accurate + f(Q-merit) Equation Three

[0064] According to the measurement error parameter = Q-merit*K1*K2, Equation Four can be obtained:

[0065] OVL calibrate ≈ OVL accurate = OVL measurement - Q-merit*K1*K2 Equation Four

[0066] Finally, Equation One can be obtained according to Equation Four.

[0067] In an embodiment, when the machine obtains the corrected second overlay error value according to the above-mentioned S101-S102, the machine can output the second overlay error value and / or the parameter (OVL para) corresponding to the second overlay error value, etc. to other devices, so that the other devices can perform subsequent processing on the wafer according to the second overlay error value and / or the parameter.

[0068] In an embodiment, the correction method provided by the present disclosure can also be applied in advanced process control (APC) to realize automatic determination and correction of overlay error values.

[0069] Figure 10 A flowchart of an embodiment of the wafer alignment detection method provided by the present disclosure is shown in Figure 10 The method shown in Figure 10 may be executed by a machine, or can be executed by a computer, a workstation, a server, or any electronic device with relevant data processing capability. In the embodiments of the present disclosure, the machine is taken as an example, but not as a limitation. As shown in Figure 10 , the wafer alignment detection method provided by the embodiments of the present disclosure includes:

[0070] S201: The machine determines a plurality of second overlay error values corresponding to the plurality of first alignment mark pairs of the to-be-detected layer of the wafer.

[0071] Specifically, the plurality of second overlay errors determined by the machine in S201 are obtained in the following manner. The machine first obtains a plurality of first overlay error values of the to-be-detected layer of the wafer, and then corrects the plurality of first overlay error values using the measurement error parameter to obtain the plurality of second overlay error values corresponding thereto. Figure 7

[0072] S202: The machine detects whether the to-be-detected layer of the wafer is aligned with the target layer according to the plurality of second overlay error values of the to-be-detected layer of the wafer determined in S201.

[0073] In an embodiment, the machine can calculate M3S, Res, and other overlay error parameters of the to-be-detected layer of the wafer according to all the second overlay error values, and finally determine whether the to-be-detected layer of the wafer is aligned with the target layer according to the overlay error.

[0074] In summary, in the alignment detection method for the wafer provided in the embodiment, the machine can detect whether the to-be-detected layer of the wafer is aligned with the target layer according to the plurality of second overlay error values after correction. Since the errors caused by the asymmetry or defects of the first alignment mark are eliminated in the second overlay error values after correction, the accuracy of the overlay error values obtained by the machine is improved, and thus the accuracy of the detection of the machine on whether the wafer is aligned is improved.

[0075] In a specific test, it is assumed that the machine obtains the overlay error parameters of the plurality of first alignment marks on the to-be-detected layer of the wafer as follows: M3S in the x direction is 2.29, M3S in the y direction is 2.99, Res in the x direction is 1.92, and Res in the y direction is 2.2. After correction, the overlay error parameters of the plurality of second alignment marks are obtained as follows: M3S in the x direction is 2.1, M3S in the y direction is 2.75, Res in the x direction is 1.72, and Res in the y direction is 2.07. It can be seen that M3S in the x direction is reduced by 8.2%, M3S in the y direction is reduced by 8.0%, Res in the x direction is reduced by 10.4%, and Res in the y direction is reduced by 5.9%.

[0076] ​In the foregoing embodiments, the method provided by the embodiments of the present disclosure is introduced, and in order to realize each function in the method provided by the embodiments of the present disclosure, the device or apparatus as a main body for executing the foregoing method can include a hardware structure and / or a software module to realize each function in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a certain function in the foregoing functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on a specific application of the technical solution and design constraint conditions.

[0077] For example, the present disclosure also provides an overlay error correction device, comprising: an acquisition module configured to acquire a first overlay error value of a first alignment mark of a to-be-detected layer of a wafer relative to a second alignment mark of a target layer; and a correction module configured to correct the first overlay error value according to a measurement error parameter corresponding to the to-be-detected layer to obtain a second overlay error value, wherein the measurement error parameter is used to indicate an influence of asymmetry of the first alignment mark or defects on the first overlay error value.

[0078] In an embodiment of the overlay error correction device of the present disclosure, the measurement error parameter is related to a measurement quality parameter, a first parameter and a second parameter of the to-be-detected layer.

[0079] The measurement quality parameter is a difference between a first derivative midpoint of the first alignment mark and a first midpoint of the first alignment mark when the first midpoint of the first alignment mark is measured; the first parameter is used to indicate a relationship between the measurement quality parameter and the first overlay error value; and the second parameter is used to indicate an influence of the measurement quality parameter on the first overlay error value measured for the to-be-detected layer.

[0080] In an embodiment, the acquisition module is further configured to acquire the measurement error parameter; or the device further comprises a determination module configured to determine the measurement quality parameter, the first parameter and the second parameter, and determine the measurement error parameter according to the measurement quality parameter, the first parameter and the second parameter, wherein the measurement error parameter is a product of the measurement quality parameter, the first parameter and the second parameter.

[0081] The implementation manner and principle of the device provided by the embodiment can refer to the method provided by the foregoing embodiments of the present disclosure, and will not be described herein.

[0082] In an embodiment, the determination module is specifically configured to acquire overlay error value training data of the to-be-detected layer, acquire measurement quality parameter training data of the to-be-detected layer, and fit the first parameter according to the overlay error value training data and the measurement quality parameter training data.

[0083] In an embodiment, the acquisition module is configured to determine a first midpoint of the first alignment mark according to the optical signal of the first alignment mark; determine a second midpoint of the second alignment mark according to the optical signal of the second alignment mark; and obtain the first overlay error value according to a difference between the first midpoint and the second midpoint.

[0084] In an embodiment, the correction module is configured to obtain the second overlay error value according to a difference between the first overlay error value and a measurement error parameter.

[0085] In an embodiment, the overlay error correction device further comprises an output module configured to output the second overlay error value and / or a parameter corresponding to the second overlay error value.

[0086] For another example, the present disclosure also provides an alignment detection device for a wafer, comprising a determination module and a detection module. The determination module is configured to determine a plurality of second overlay error values of a layer to be detected of the wafer. The detection module is configured to determine whether the layer to be detected is aligned with a target layer according to the plurality of second overlay error values.

[0087] It should be noted that the division of each module of the above device is only a logical functional division, and all or part of the modules can be integrated into one physical entity or physically separated when actually implemented. The modules can be all implemented in the form of software invoked by a processing element, all implemented in the form of hardware, or some modules implemented in the form of software invoked by a processing element and some modules implemented in the form of hardware. For example, the processing module can be a separately established processing element, or can be integrated in a chip of the above device, and in addition, the processing module can be in the form of program code stored in a memory of the above device and invoked and executed by a processing element of the above device. The implementation of other modules is similar. In addition, all or part of the modules can be integrated together or independently implemented. The processing element described herein can be an integrated circuit having a signal processing capability. In the implementation process, each step of the above method or each module can be completed by an integrated logic circuit of hardware or an instruction in the form of software in the processing element.

[0088] For example, the above modules can be one or more integrated circuits configured to implement the above methods, such as one or more application specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field programmable gate arrays (FPGAs), or the like. For another example, when a certain module above is implemented by a form of invoking program code by a processing element, the processing element can be a general purpose processor, such as a central processing unit (CPU) or other processor that can invoke program code. For another example, the modules can be integrated together to be implemented in a form of a system on a chip (SOC).

[0089] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present disclosure are generated. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center and the like integrated with one or more available media. The available medium can be a magnetic medium (for example, floppy disk, hard disk, magnetic tape), optical medium (for example, DVD), or semiconductor medium (for example, solid state disk (SSD)) and the like.

[0090] For example, the present disclosure also provides an electronic device, including: a processor and a memory; wherein the memory stores a computer program, and the processor can execute the computer program. When the processor executes the computer program, the processor can be used to execute the steps in any method of the foregoing embodiments of the present disclosure.

[0091] The present disclosure also provides a computer readable storage medium storing a computer program, the computer program being executable to perform the steps in any of the methods of the preceding embodiments of the present disclosure.

[0092] The present disclosure also provides a chip for executing instructions, the chip being configured to perform the steps in any of the methods of the preceding embodiments of the present disclosure.

[0093] Those skilled in the art can understand that all or part of the steps of the foregoing method embodiments can be completed by a program instruction related hardware. The foregoing program can be stored in a computer readable storage medium. The program, when executed, performs the steps of the foregoing method embodiments; and the foregoing storage medium includes various media capable of storing program codes, such as ROM, RAM, magnetic disk, or optical disk.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for correcting overprinting errors, characterized in that, include: Obtain the first alignment error value of the first alignment mark of the layer to be inspected on the wafer relative to the second alignment mark of the target layer; The first overlay error value is corrected according to the measurement error parameter corresponding to the layer to be tested to obtain the second overlay error value; the measurement error parameter is used to indicate the influence of the asymmetry or defect of the first alignment mark on the first overlay error value. The measurement error parameter is related to the measurement quality parameter, the first parameter, and the second parameter of the layer to be detected. Wherein, the measurement quality parameter is the difference between the midpoint of the first derivative of the first alignment mark and the first midpoint of the first alignment mark when measuring the first midpoint of the first alignment mark; The first parameter is used to indicate the relationship between the measurement quality parameter and the first overlay error value; The second parameter is used to indicate the influence of the measurement quality parameter on the first set of etching error values ​​obtained by measuring the layer to be tested.

2. The method according to claim 1, characterized in that, Also includes: Obtain the measurement error parameters; Alternatively, the measurement quality parameter, the first parameter, and the second parameter are determined, and the measurement error parameter is determined based on the measurement quality parameter, the first parameter, and the second parameter, wherein the measurement error parameter is the product of the measurement quality parameter, the first parameter, and the second parameter.

3. The method according to claim 2, characterized in that, The method for determining the first parameter includes: Obtain training data of the overlay error values ​​of the layer to be detected; Obtain the training data of the measurement quality parameters of the layer to be detected; The first parameter is obtained by fitting the training data of the overlay error value and the training data of the measurement quality parameter.

4. The method according to any one of claims 1-3, characterized in that, The acquisition of the first alignment error value of the first alignment mark of the layer to be inspected on the wafer relative to the second alignment mark of the target layer includes: The first midpoint of the first alignment mark is determined based on the optical signal of the first alignment mark; The second midpoint of the second alignment mark is determined based on the optical signal of the second alignment mark; The first overlay error value is obtained based on the difference between the first midpoint and the second midpoint.

5. The method according to any one of claims 1-3, characterized in that, The step of correcting the first set of etching error values ​​based on the measurement error parameters corresponding to the layer to be detected to obtain the second set of etching error values ​​includes: The second set of engraving error values ​​is obtained based on the difference between the first set of engraving error values ​​and the measurement error parameters.

6. The method according to any one of claims 1-3, characterized in that, After obtaining the second set of engraving error values, the process also includes: Output the second set of engraving error value and / or the parameters corresponding to the second set of engraving error value.

7. A wafer alignment detection method, characterized in that, include: Determine multiple sets of second set of etching error values ​​corresponding to multiple first alignment marks of the layer to be inspected on the wafer; The second set of engraving error values ​​is obtained according to the method described in any one of claims 1-6; Based on the multiple sets of second-set etching error values, it is determined whether the layer to be detected is aligned with the target layer.

8. A device for correcting overprinting errors, characterized in that, include: The acquisition module is used to acquire the first alignment error value of the first alignment mark of the layer to be inspected on the wafer relative to the second alignment mark of the target layer; The correction module is used to correct the first overlay error value according to the measurement error parameter corresponding to the layer to be detected, so as to obtain the second overlay error value; the measurement error parameter is used to indicate the influence of the asymmetry or defect of the first alignment mark on the first overlay error value. The measurement error parameter is related to the measurement quality parameter, the first parameter, and the second parameter of the layer to be detected. Wherein, the measurement quality parameter is the difference between the midpoint of the first derivative of the first alignment mark and the first midpoint of the first alignment mark when measuring the first midpoint of the first alignment mark; The first parameter is used to indicate the relationship between the measurement quality parameter and the first overlay error value; The second parameter is used to indicate the influence of the measurement quality parameter on the first set of etching error values ​​obtained by measuring the layer to be tested.

9. The apparatus according to claim 8, characterized in that, The acquisition module is also used to acquire the measurement error parameters; Alternatively, the device may further include: a determining module; the determining module is configured to determine the measurement quality parameter, the first parameter and the second parameter, and determine the measurement error parameter based on the measurement quality parameter, the first parameter and the second parameter, wherein the measurement error parameter is the product of the measurement quality parameter, the first parameter and the second parameter.

10. The apparatus according to claim 9, characterized in that, The determining module is specifically used for, Acquire training data of overlay error values ​​of the layer to be tested, acquire training data of measurement quality parameters of the layer to be tested, and fit the first parameter based on the training data of overlay error values ​​and the training data of measurement quality parameters.

11. The apparatus according to any one of claims 8-10, characterized in that, The acquisition module is used for, The first midpoint of the first alignment mark is determined based on the optical signal of the first alignment mark; the second midpoint of the second alignment mark is determined based on the optical signal of the second alignment mark; and the first overlay error value is obtained based on the difference between the first midpoint and the second midpoint.

12. The apparatus according to any one of claims 8-10, characterized in that, The correction module is used for, The second set of engraving error values ​​is obtained based on the difference between the first set of engraving error values ​​and the measurement error parameters.

13. The apparatus according to any one of claims 8-10, characterized in that, Also includes: The output module is used to output the second set of engraving error values ​​and / or the parameters corresponding to the second set of engraving error values.

14. A wafer alignment and inspection device, characterized in that, include: The determination module is used to determine multiple sets of second set of etching error values ​​corresponding to multiple first alignment marks of the layer to be inspected on the wafer; The second set of engraving error values ​​is obtained according to the method described in any one of claims 1-6; The detection module is used to determine whether the layer to be detected is aligned with the target layer based on the plurality of second set of etching error values.

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