Measurement method, measurement apparatus, lithographic apparatus, and article manufacturing method

Abstract

The invention provides a measurement method, a measurement apparatus, a lithographic apparatus, and an article manufacturing method. The measurement method includes: a preliminary measurement step of performing a preliminary measurement for obtaining signal information obtained by detecting a plurality of targets formed on a substrate using measurement light a plurality of times while changing a parameter value of a measurement parameter; an obtaining step of obtaining a relationship between the parameter value and the signal information based on a result of the preliminary measurement performed for multiple times; a determination step of determining a target to be subjected to main measurement in the plurality of targets based on the obtained relationship; and a main measurement step of performing main measurement on the determined target.

Description

Technical Field

[0001] The present invention relates to a measuring method, a measuring device, a photolithography device and an article manufacturing method. Background Art

[0002] In lithography equipment, such as exposure equipment, used in lithography processes, the alignment accuracy between the shot region on the substrate and the master, as well as the overlay accuracy between different layers on the substrate, are crucial. One method for improving alignment and overlay accuracy involves selecting measurement marks or measurement processing conditions that are less susceptible to degradation in measurement accuracy caused by changes in substrate properties. This approach maximizes the intensity and quality of the measurement signal from the measurement marks, achieving high-precision measurements.

[0003] Japanese Patent Laid-Open No. 2023-184422 describes a method for determining the value of a measurement parameter to improve the measurement accuracy of a mark formed on a substrate. The method obtains a sensitivity indicating how the measured value changes with respect to a change in the parameter value, and determines the parameter value to be adopted based on the sensitivity distribution.

[0004] However, if the shape or characteristics of a mark formed on a substrate change, the intensity and quality of a measurement signal from the mark may decrease, which may result in a decrease in measurement accuracy. Summary of the Invention

[0005] The present disclosure provides a technique that facilitates achieving high measurement accuracy.

[0006] The present disclosure provides, in its first aspect, a measurement method, comprising: a preliminary measurement step of performing preliminary measurements multiple times for obtaining signal information obtained by detecting multiple targets formed on a substrate using measurement light while changing the parameter value of a measurement parameter; an acquisition step of acquiring, based on results of the preliminary measurements performed multiple times, a relationship between the parameter value and the signal information; a determination step of determining, based on the acquired relationship, a target among the multiple targets for which a main measurement should be performed; and a main measurement step of performing a main measurement on the determined target.

[0007] In its second aspect, the present invention provides a method for manufacturing an article, which comprises: measuring the position of a target on a substrate according to the measurement method described in the first aspect, and transferring a pattern to the substrate based on the position of the target; and obtaining the article by processing the substrate with the transferred pattern.

[0008] In its third aspect, the present invention provides a measuring device, which includes: a measuring unit; and a controller, wherein the controller is constructed to: control the measuring unit so that while changing the parameter value of the measurement parameter, preliminary measurements for obtaining signal information obtained by detecting multiple targets formed on a substrate using measurement light are performed multiple times, based on the results of the preliminary measurements performed multiple times, the relationship between the parameter value and the signal information is acquired, based on the acquired relationship, the target among the multiple targets that should be subjected to main measurement is determined, and the measuring unit is controlled to perform main measurement on the determined target.

[0009] In its fourth aspect, the present invention provides a lithography device, comprising: a measuring device according to the third aspect, which is configured to measure the position of a mark provided on a substrate; and a positioning mechanism, which is configured to position the substrate based on the position of the mark measured using the measuring device, wherein the lithography device is configured to transfer a pattern of the substrate.

[0010] In its fifth aspect, the present invention provides a method for manufacturing an article, comprising: transferring a pattern onto a substrate using the photolithography apparatus according to the fourth aspect; and obtaining the article by processing the substrate to which the pattern has been transferred.

[0011] Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A and Figure 1B is a diagram showing the configuration of a measuring device;

[0013] Figure 2A and Figure 2B is a diagram showing an example of a sample area of ​​a substrate;

[0014] Figure 3A and Figure 3B is a diagram showing a configuration example of a measurement pattern and an example of derivation of a measurement value;

[0015] Figure 4A and Figure 4B is a diagram for explaining the center wavelength and wavelength bandwidth as measurement parameters;

[0016] Figure 5 is a flowchart showing the sequence of measurement processing;

[0017] 6A to 6D is a diagram for explaining the measurement process;

[0018] 7A to 7C A diagram for explaining a method of determining a measurement processing condition based on a relationship between a measurement parameter and signal information;

[0019] Figure 8 A diagram for explaining a method of determining a processing area as a measurement processing condition;

[0020] Figure 9 is a diagram for illustrating the estimation of overlay measurement values;

[0021] Figure 10 is a flowchart showing the sequence of measurement processing;

[0022] Figure 11 is a flowchart showing the sequence of measurement processing;

[0023] Figure 12 A diagram for explaining a method of determining a processing area as a measurement processing condition;

[0024] Figure 13 is a flowchart showing the sequence of measurement processing;

[0025] Figure 14 is a diagram showing the configuration of an exposure device; and

[0026] Figure 15 is a flowchart showing the sequence of exposure processing. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claims. While various features are described in the embodiments, the present invention is not limited to embodiments requiring all of these features, and multiple such features may be appropriately combined. Furthermore, in the drawings, identical or similar structures are given identical reference numerals, and redundant descriptions thereof are omitted.

[0028] <First embodiment>

[0029] Figure 1A 1 is a diagram showing the structure of the measuring device 100 according to this embodiment. In the specification and the accompanying drawings, directions will be indicated on the XYZ coordinate system, and in the XYZ coordinate system, the horizontal plane is defined as the XY plane. Typically, the substrate 73 is placed on the substrate stage WS so that the surface of the substrate 73 becomes parallel to the horizontal surface (XY plane). In the following description, directions orthogonal to each other in the plane of the upper surface of the substrate stage WS on which the substrate 73 is placed are defined as the X-axis and the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is defined as the Z-axis. In addition, in the following description, the directions parallel to the X-axis, the Y-axis, and the Z-axis in the XYZ coordinate system are referred to as the X-direction, the Y-direction, and the Z-direction, respectively.

[0030] The measuring device 100 can be configured as a detection device that measures or detects the position of a target formed on the substrate 73. Alternatively, the measuring device 100 can be configured as an overlay inspection device that measures the relative positions between multiple targets provided in different layers of the substrate 73. The target can be a mark or pattern formed on the substrate 73. The pattern can be a pattern formed only for the purpose of being used as a mark, or it can be a predetermined device pattern. Hereinafter, the measurement target object used as a target will be collectively referred to as a "pattern". The measuring device 100 includes a substrate stage WS that holds the substrate 73, an imaging unit 50 (measuring unit), a controller 11, and an interface 12.

[0031] The substrate 73 can be used, for example, to manufacture devices such as semiconductor devices or liquid crystal display devices. The substrate 73 can be, for example, a wafer or a glass substrate. The substrate stage WS holds the substrate 73 via a substrate chuck (not shown) and can be driven or positioned by a substrate drive mechanism (not shown). The substrate drive mechanism includes a linear motor, etc., and can move the substrate 73 held by the substrate stage WS by driving the substrate stage WS in the X direction, Y direction, Z direction, and rotational directions around each axis. The position of the substrate stage WS is monitored by, for example, a 6-axis laser interferometer 13, and the substrate stage WS is driven to a predetermined position under the control of the controller 11.

[0032] The controller 11 is formed by a computer (information processing device) including a CPU, memory, etc., and comprehensively controls the components of the measuring device 100 according to, for example, a program stored in a storage unit. Based on the measurement results obtained by the imaging unit 50, more specifically, based on the image obtained by imaging the measurement pattern formed on the substrate 73, the controller 11 can perform various correction processes (arithmetic processing). The interface 12 may include a display device and an input device. The user can use the interface 12 to specify the position of a projection area serving as a measurement target among the multiple projection areas formed on the substrate 73, or to specify a measurement pattern within the projection area.

[0033] Will refer to Figure 1BThe configuration of the imaging unit 50 will be described. The imaging unit 50 may include an illumination system that illuminates the substrate 73 using light from the light source 61, and an imaging system (detection system) that forms an image of the measurement pattern 72 formed on the substrate 73 on the imaging element 75. The light from the light source 61 is guided to the illumination aperture stop 64 via lenses 62 and 63. The light source 61 may be, for example, a laser light source, an LED, or a halogen lamp, but is not limited thereto. The light that has passed through the illumination aperture stop 64 is guided to the polarization beam splitter 68 via a lens 65, a reflective mirror 66, and a lens 67. The P-polarized light that has passed through the beam splitting surface of the polarization beam splitter 68 passes through the aperture stop 69, is then converted into circularly polarized light via a λ / 4 wave plate 70, and is Koehler-illuminated on the measurement pattern 72 formed on the substrate 73 via the objective lens 71.

[0034] Light reflected, diffracted, and scattered by the Köhler-illuminated measurement pattern 72 passes through the objective lens 71 and the λ / 4 wave plate 70 and is guided to the aperture stop 69. The polarization state of the light from the measurement pattern 72 is circularly polarized, opposite to the circular polarization of the light that illuminates the measurement pattern 72. Upon passing through the λ / 4 wave plate 70, the light is converted from circularly polarized light to S-polarized light. The S-polarized light passes through the aperture stop 69, is reflected by the beam splitting surface of the polarization beam splitter 68, and is guided to the imaging element 75 via the lens 74.

[0035] Note that the illumination optical system may be equipped with a light quantity adjustment unit (not shown) or a wavelength adjustment unit (not shown). The light quantity adjustment unit may include, for example, a plurality of ND filters having different transmittances for the light from the light source 61. The plurality of ND filters are arranged in a switchable state. The light quantity adjustment unit can adjust the intensity of the light illuminating the substrate 73 by controlling the switching of the ND filters.

[0036] The wavelength adjustment unit may include, for example, a variable wavelength element and a drive mechanism for driving the variable wavelength element. The drive mechanism may include a linear motor or the like, and drives the variable wavelength element in a predetermined direction (e.g., the X direction) to adjust the wavelength (e.g., the center wavelength and the wavelength bandwidth) of the light (measurement light) illuminating the measurement pattern 72.

[0037] Note that as a method for changing the wavelength of light from measurement pattern 72, in addition to the aforementioned method using wavelength filters or variable wavelength elements, there are also methods using a color sensor or multispectral sensor, in which different wavelength filters are placed for each pixel. Alternatively, a method using a hyperspectral sensor including a diffractive optical element or multiple cameras including a wavelength splitter such as a dichroic prism and multiple imaging elements can be used. Thus, imaging element 75 can be used to detect multiple light components of different wavelengths from the light from measurement pattern 72.

[0038] The controller 11 can acquire the position of the measurement pattern 72 based on the position information of the substrate stage WS obtained by the laser interferometer 13 and the signal waveform obtained by detecting the image of the measurement pattern 72. The intensity of the signal waveform can be adjusted by at least one of controlling a light amount adjustment unit (ND filter) provided in the illumination optical system of the imaging unit 50, controlling the output of the light source 61, and controlling the accumulation time of the imaging element 75.

[0039] Note that in the imaging system of the imaging unit 50, a detection aperture stop can be formed by arranging multiple lenses between the polarization beam splitter 68 and the imaging element 75. Furthermore, each of the illumination aperture stop 64 and the detection aperture stop can be equipped with multiple aperture stops capable of setting different numerical apertures for the illumination system and the imaging system, and the multiple aperture stops can be switched. This allows adjustment of the σ value, a coefficient representing the ratio of the numerical aperture of the illumination system to the numerical aperture of the imaging system. Furthermore, as a method for detecting light from the measurement pattern 72, dark field detection can be used. For example, the aperture diameter of the illumination aperture stop 64 or the detection aperture stop is controlled to shield the zeroth-order diffracted light from the measurement pattern 72 and detect only the higher-order diffracted light or scattered light.

[0040] A method of photographing a measurement pattern formed on the substrate 73 and measuring the position of the substrate 73 using the measurement device 100 will be described below. Figure 2A and Figure 2B This diagram shows a sample area for multiple projection areas formed on substrate 73. Position measurement of the measurement pattern is performed on the measurement pattern present in each sample area. Here, the sample area refers to an area that includes both an area where a device pattern is formed and an area near that area that includes scribe lines. Figure 2A and Figure 2B The selection of sample areas shown is merely an example, and the number and positions of the sample areas may be arbitrarily varied depending on the desired substrate position measurement accuracy and throughput.

[0041] Figure 3A is a diagram showing an example of a measurement pattern 72 formed on a substrate 73. The measurement apparatus 100 generally acquires position information in the X and Y directions of the substrate 73. For simplicity, only the X pattern for measuring the position in the X direction will be described here.

[0042] In this embodiment, the measurement pattern 72 may include a plurality of different patterns. The measurement pattern 72A and the measurement pattern 72B may be patterns formed by a plurality of line elements (line-and-space patterns). For example, the measurement pattern 72 may include a measurement pattern 72A formed by line elements A11 to A14 and a measurement pattern 72B formed by line elements A21 to A24. The line-and-space pattern may have gaps between adjacent line elements. For example, Figure 3A As shown, measurement pattern 72A and measurement pattern 72B have a configuration in which line elements having widths W1 and W2 and gaps having widths W3 and W4 are periodically repeated. The width of at least one of the line elements and the gaps differs between measurement pattern 72A and measurement pattern 72B. Not only the width of the line elements and the gaps, but also at least one of the pattern design, the number of patterns, and the formation position in the Z direction on the substrate preferably differ. Note that the number of measurement patterns 72 is not limited to a specific number, and three or more measurement patterns may be formed.

[0043] exist Figure 3A , area 75W indicates the imaging area in imaging element 75 of imaging unit 50. With respect to area 75W, substrate 73 is aligned with imaging unit 50 so that measurement pattern 72 fits within area 75W. Thus, light components from multiple different measurement patterns can be detected simultaneously. Measurement pattern 72 is roughly measured, and controller 11 sets multiple different processing areas in imaging element 75 based on the results of the rough measurement. Therefore, for example, when processing area 75WA and processing area 75WB are set for measurement pattern 72A and measurement pattern 72B, respectively, and measurements are performed, position information can be acquired for each of measurement pattern 72A and measurement pattern 72B.

[0044] Figure 3B : This diagram shows the results obtained by imaging measurement pattern 72A with imaging element 75 and performing photoelectric conversion on the signal intensity in the X direction on the imaging element surface (not shown). Reference numeral S72A indicates signal intensity information including peak signals PA11 to PA14, two of which correspond to each of line elements A11 to A14. From signal intensity information S72A, a measurement value M1A of measurement pattern 72A relative to the reference position of imaging element 75 can be obtained. Similarly, measurement value M2A of measurement pattern 72B can be obtained. Note that measurement value M1A is not limited to a measurement value relative to the reference position of imaging element 75; for example, a position relative to a preset measurement template or design value can be obtained as a measurement value.

[0045] Next, the measurement parameters will be described. The measurement device 100 can preferably perform measurements based on a set parameter value for at least one parameter. The at least one measurement parameter may include at least one of the center wavelength, wavelength bandwidth, σ value, and polarization properties of the light (measurement light) illuminating the measurement pattern. The polarization properties may be polarization properties in the optical path of the measurement device 100 or the measurement unit. The at least one measurement parameter may include various arithmetic processing parameters set when the controller 11 calculates the measurement value based on the image information of the measurement pattern.

[0046] The following describes measurement parameters related to the wavelength of light used for measurement as an example. As measurement parameters related to the wavelength of light used for measurement, for example, the wavelength and the bandwidth of the wavelength can be exemplified. Figure 4A is a diagram showing wavelength characteristics of light components having different center wavelengths, the two different center wavelengths being indicated by WL1 and WL2. Figure 4B is a diagram showing wavelength characteristics of light components having the same central wavelength but different wavelength bandwidths, the two different wavelength bandwidths being indicated by ΔWL1 and ΔWL2 .

[0047] The characteristics of the measurement pattern on the substrate, such as the physical properties of the material, structure, shape, etc., can change depending on the process used to obtain the substrate. Therefore, to achieve accurate measurement, it is important to match the measurement parameters with the characteristics of the measurement pattern.

[0048] However, the characteristics of the measurement pattern may vary locally. For example, the characteristics of the measurement pattern may vary depending on the measurement pattern or the characteristic portions (pattern features) that form the measurement pattern. Even if center wavelength WL1 is the optimal measurement parameter value for line element A11, center wavelength WL1 may not necessarily be the optimal measurement parameter value for line element A14. Therefore, when using measurement pattern 72 as a processing area for measurement, it is difficult to accurately determine the optimal measurement parameter value.

[0049] In this embodiment, preliminary measurements (preliminary measurements) are first performed multiple times while varying the values ​​of measurement parameters to obtain signal information obtained by detecting an image of a target formed on a substrate. The relationship between the parameter values ​​and the signal information is then determined based on the results of these multiple preliminary measurements. Next, based on this obtained relationship, the processing area of ​​the substrate where the main measurement should be performed is determined. The main measurement is then performed on this determined processing area.

[0050] The following will refer to Figure 5 The sequence of the measurement process according to the present embodiment will be described. The measurement process is performed by the controller 11 which comprehensively controls each unit of the measurement device 100 .

[0051] In step S501 , the controller 11 transfers the substrate 73 to the measurement range of the imaging unit 50 and pre-aligns the substrate 73 so that the movement of the substrate stage WS in the X direction matches the arrangement direction of the multiple shot areas to be exposed on the substrate 73 in the X direction.

[0052] In step S502, the controller 11 acquires signal information from the measurement pattern 72 while changing at least one measurement parameter. Here, the signal information may be at least one of contrast, signal strength information, and position information as a signal evaluation value obtained from the image. The signal evaluation value will be described later.

[0053] In step S503, the controller 11 obtains data on the signal information on the measurement parameter change obtained in step S502. The data on the signal information on the measurement parameter change will be described later.

[0054] In step S504, the controller 11 may determine measurement processing conditions based on the data obtained in step S503. The measurement processing conditions may be, for example, at least one of a processing region, a sample region, and a measurement parameter. Here, the processing region is a processing region corresponding to a line element. For example, multiple processing regions may be set based on the number of line elements. In this case, a weight to be added to each processing region may also be determined. Even for multiple different measurement patterns, the processing regions may be similarly set, and the weight to be added may be determined.

[0055] In step S505, the controller 11 sets the measurement processing conditions according to the measurement processing conditions determined in step S504. The setting of the measurement processing conditions is accomplished by, for example, storing the measurement processing conditions in a predetermined area of ​​a storage unit.

[0056] In step S506 , the controller 11 obtains position information of the measurement pattern 72 and performs statistical processing on the position information to calculate the position of the substrate 73 .

[0057] The signal evaluation value will be described below. The signal evaluation value refers to an index indicating the quality of signal intensity information generated based on the output of the imaging element 75 (imaging unit 50). Figure 6Ais a diagram exemplarily illustrating the reflected light components from the measurement pattern 72 and the non-pattern portion on a cross section of a substrate 73. The substrate 73 is formed of a first layer L1 and a second layer L2, and includes two boundary surfaces S1 and S2. On the boundary surface S1, the measurement pattern 72 has a step height d relative to the non-pattern portion. Let L1A be the reflected light from the measurement pattern 72 on the boundary surface S1, L1B be the reflected light from the non-pattern portion, and L2A and L2B be the reflected light components from the measurement pattern 72 and the non-pattern portion on the boundary surface S2. In the imaging unit 50, the interference light between the reflected light L1A and the reflected light L2A, and the interference light between the reflected light L1B and the reflected light L2B are the reflected light LA ​​from the measurement pattern 72 and the reflected light LB from the non-pattern portion, and each light is detected.

[0058] Figure 6B is a diagram showing an example of signal strength information about a location X, and includes Figure 6A The figure shows reflected light LA ​​from the pattern portion and reflected light LB from the non-pattern portion. Here, the smaller the signal intensity difference between reflected light LA ​​and reflected light LB, the lower the signal contrast, making it more difficult to detect the position of the measurement pattern. The signal intensity difference between reflected light LA ​​and reflected light LB changes depending on the phase difference Δ caused by the step difference d of measurement pattern 72. Phase difference Δ is expressed by the following equation (1) using the refractive index n of second layer L2, step difference d, and wavelength λ.

[0059] Δ=2nd×2π / λ...(1)

[0060] According to equation (1), if the refractive index n or the step difference d of the second layer L2 changes in the measurement pattern 72, the phase difference Δ changes. As described above, the change in phase difference Δ causes a change in signal contrast, and at the same time, measurement errors may occur, and measurement accuracy may be reduced.

[0061] Figure 6C This graph shows an example of signal intensity information for a pattern. The horizontal axis represents position, while the vertical axis represents signal intensity. Because the pattern and non-pattern areas on the substrate have different structures, the signal intensity varies depending on the position of each area. One type of characteristic information for a measured pattern is a value obtained by quantifying the contrast of the measurement signal.

[0062] For example, in Figure 6D In the example, let T L is the maximum value of the signal strength of the left section of the measurement signal, B L is the minimum value, T R is the maximum signal strength of the right segment, and B R As shown in the following formula (2), the contrast EC in the measurement signal can be obtained as characteristic information.

[0063] EC={(T L -B L ) / (T L +B L )+(T R -B R ) / (T R +B R )} / 2...(2)

[0064] In addition, for example, it is possible to obtain Figure 6D The asymmetry ES of the measurement signal is shown as characteristic information. The asymmetry of the measurement signal can be calculated according to the following equation (3).

[0065] ES=(T L -B L ) / (T L +B L )-(T R -B R ) / (T R +B R )...(3)

[0066] The asymmetry calculation method is not limited to formula (3). For example, the center position of the measurement signal can be defined, and the asymmetry of the measurement signal can be defined based on the signal strength within a predetermined position range in each segment in the left segment and the right segment relative to the center position.

[0067] 7 and Figure 8 The following describes the method for determining measurement processing conditions based on the relationship between the measurement parameter and signal information in steps S503 and S504. First, as an example, the method will be described for determining measurement processing conditions when the measurement parameter is the center wavelength and the signal information is the contrast of each of a plurality of line elements. Here, an example will be described in which the processing area is determined as the measurement processing condition. Contrast data regarding changes in the center wavelength is used as an indicator to determine the measurement processing conditions to be used in the measurement in step S507.

[0068] Figure 7A is a graph showing the relationship between contrast and central wavelength. The contrast is in the processing area 75WA ( Figure 3A ) is obtained from the measurement pattern 72A. The horizontal axis represents the center wavelength (referred to as "wavelength"), and the vertical axis represents the contrast of the measurement pattern 72A. Here, the center wavelength WL3 and the center wavelength WL4 each refer to the center wavelength of light. Figure 7A, the contrast of the measurement pattern 72A at the center wavelength WL3 is C3a, and the contrast at the center wavelength WL4 is C4a. Here, the contrast of the measurement pattern 72A is the result of averaging the contrast values ​​obtained by the peak signals PA11 to PA14 ( Figure 3B ). Then, for example, it is determined whether (the maximum value of) the obtained contrast value exceeds a threshold value SH. The threshold value SH can be determined using previously acquired characteristic information or position information of a plurality of substrates. When the measurement parameter value is selected in the above manner, measurement errors associated with process changes can be reduced. If the measurement parameter value is selected based on position information of the measurement pattern rather than signal information, a parameter value can be selected that indicates a small sensitivity of the measurement value to changes in the measurement parameter.

[0069] Figure 7B Graph showing the relationship between the center wavelength and contrast for each of the line elements A11 to A14 of the measurement pattern 72A. Even in the same measurement pattern, the process may cause film unevenness or shape differences for each pattern. Therefore, even for each of the plurality of line elements, it is necessary to determine whether the (maximum) contrast value exceeds the threshold value SH. Based on Figure 7B , the contrast values ​​(eg, the maximum contrast value) of the line elements A11, A12, and A13 exceed the threshold SH, but the contrast value of the line element A14 is less than the threshold SH. Figure 8 As shown in FIG. 7A , the area outside the line element A14 is set as a processing area (as a measurement processing condition), as in the processing area 75WC shown in FIG. Here, a plurality of line elements have been described as an example. However, the processing area can be set for each image in a plurality of measurement patterns or device patterns in which the pattern design, the number of line elements, or the formation position in the Z direction on the substrate vary.

[0070] In the above determination method, the target has a pattern consisting of multiple line elements, the measurement parameter is the central wavelength of light illuminating the measurement pattern, and the signal information is the contrast of each of the multiple line elements. In this determination method, a relationship between the central wavelength and the contrast is obtained for each of the multiple line elements. Line elements whose maximum contrast value in this relationship is less than a threshold value are excluded from the main measurement.

[0071] (Sample area determination method)

[0072] The method for determining a processing area as a measurement processing condition when the measurement parameter is the center wavelength and the signal information is contrast has been described above. Next, a method for determining a sample area as a measurement processing condition when the measurement parameter is the center wavelength and the signal information is the asymmetry of the measurement signal will be described. Here, the multiple targets are patterns each formed by multiple line elements and are arranged in each of the multiple predetermined projection areas set as sample area candidates on substrate 73.

[0073] Figure 7C is a diagram showing the relationship between the central wavelength obtained in each of the projection areas 151 to 154 and the asymmetry of the measurement signal ( Figure 2A ). The horizontal axis represents the central wavelength, and the vertical axis represents the asymmetry of the measurement signal. The asymmetry of the measurement signal in each sample area may lead to measurement fraud, so it is preferable that the asymmetry is small. It is determined whether the amplitude of the asymmetry of the measurement signal does not exceed the threshold value SH, and the sample area is set based on the determination result. For example, in Figure 7C , the minimum value of the asymmetry of the measurement signal in the projection region 154 exceeds the threshold value SH. Therefore, the projection region 154 is excluded from the sample region.

[0074] By performing the above-described determination method, measurement errors associated with process variations can be reduced, and accurate position measurement can be achieved.

[0075] The following will describe the processing in the case where a value is added to the position of the measurement pattern 72. Figure 8 The weights of the line elements A11 to A14 shown are set as measurement processing conditions. Here, the position of the pattern is represented by the weighted average of the positions of multiple line elements. For example, if N11 to N14 are the weight coefficients of the pattern positions (PA11 to PA14), and P72A is the position of the measured pattern 72A, the position P72A of the measured pattern 72A can be calculated by the following formula:

[0076] P72A=(N11·PA11+N12·PA12+N13·PA13+N14·PA14) / 4...(4)

[0077] Alternatively, for example, weights may be added to the multiple different measurement patterns 72A and 72B that form the measurement pattern 72. Furthermore, weights may be added to the multiple measurement patterns 72 formed at different locations on the substrate. This allows the positions of the measurement patterns to be accurately determined regardless of process variations in the region of the measurement pattern 72 or in the position on the substrate.

[0078] According to the above determination method, for each of a plurality of predetermined projection areas serving as sample area candidates, a relationship between the center wavelength and the asymmetry of the measurement signal is obtained. Among the plurality of predetermined projection areas, projection areas whose minimum asymmetry value in this relationship exceeds a threshold are excluded from the sample area candidates.

[0079] A method based on the acquired overlay measurement value will be described below as one of the methods for calculating the weight coefficient.

[0080] Figure 9 This diagram shows the relationship between a pattern, the position correction amount (position correction coefficient) for the substrate 73 based on the pattern, and the overlay measurement value of the formed pattern. For example, the substrate position correction amount GA11 is calculated by performing global alignment based on the position measurement results of the line element A11. Furthermore, the overlay measurement value OLA is obtained by forming a pattern on the substrate based on the substrate position correction amount GA11.

[0081] Note that when the position measurement result of the pattern A12 is used, the overlay measurement value OLB can be estimated from the following equation based on the position correction amounts GA11 and GA12 of the substrate and the overlay measurement value OLA.

[0082] OLB=OLA+F(GA11,GA12)...(5)

[0083] Here, F(GA11, GA12) indicates a function including GA11 and GA12. As a typical example, F(GA11, GA12) may be GA11-GA12. In this case, the overlay measurement value OLB is calculated as a value obtained by adding the difference between the position correction amounts GA11 and GA12 of the substrate to the overlay measurement value OLA. Detailed examples of the position correction amount are the position deviation (offset), magnification error, and rotation error of the substrate. In the arithmetic processing, the difference between the position correction amounts is preferably calculated, and the difference between the position correction amounts is added to the plurality of projection areas on the substrate 73.

[0084] In the measurement apparatus according to this embodiment, within the imaging area obtained from the imaging unit 50, a processing region is set for each of the multiple line elements forming the measurement pattern, and the position of the substrate is measured. Then, based on the measurement values ​​obtained for each processing region, a position correction amount for the substrate is calculated. Thus, position correction amounts for the substrate are calculated for each of the multiple processing regions, and overlay measurement values ​​for each of the multiple processing regions can be estimated based on the positional information of the pattern formed on the substrate.

[0085] It is preferable to determine the weight coefficient to be added to each processing area (i.e., each line element in the measurement pattern) so that the overlay measurement value of each projection area in the plurality of projection areas on the substrate is not greater than an allowable value (e.g., a minimum value). The weight can be set as a parameter, and the weight coefficient for which the overlay measurement value is not greater than the allowable value (e.g., the minimum value) can be calculated. In the example, a processing area including only one line element among the plurality of line elements included in the measurement pattern is set by setting the weight coefficient of one line element to 1 and the weight coefficients of the remaining line elements to 0. Note that the weight coefficient may be a negative number instead of a positive number.

[0086] Alternatively, the difference between the acquired pattern position information and the design value (target value) can be determined, and a weighting factor can be set to minimize the difference. Alternatively, a weighting factor can be set based on the acquired measurement pattern signal information and the number of line elements. Furthermore, the weighting factor can be set to minimize variations in signal information across multiple projection areas on substrate 73.

[0087] Here, in step S505, the weighting coefficients added to the multiple line elements forming the measurement pattern do not need to be the same for all sample areas on substrate 73. For example, the weighting coefficients can be changed depending on the position of the sample area relative to substrate 73. The weighting coefficients do not need to be the same for all measurement directions on substrate 73. For example, different weighting coefficients can be set for measurements in the X direction and measurements in the Y direction. In this way, the weighting coefficients for the multiple line elements forming the measurement pattern are determined.

[0088] Regarding the pattern position measurement in step S506, detailed statistical processing will be described. For example, the positions of the plurality of shot areas formed on the substrate 73 can be calculated by performing global alignment measurement based on the position information of the measurement patterns in the plurality of sample areas.

[0089] In this embodiment, pattern position measurement can be performed by the controller 11. However, the present invention is not limited thereto. For example, pattern position measurement can be performed by an online host device that controls other devices in a factory where the measurement device 100 is installed in an integrated manner via a network. Furthermore, the position measurement results can be transmitted, for example, via the online host device to an exposure device that performs exposure as the next step of the substrate 73.

[0090] As described above, in the first embodiment, light from a pattern formed on a substrate is imaged, the relationship between measurement parameters and signal information is acquired, and measurement processing conditions are determined based on this acquired relationship. The position of the substrate is calculated based on these measurement processing conditions, thereby accurately measuring the target object.

[0091] <Second embodiment>

[0092] As a second embodiment, a measurement apparatus and method for measuring the quality of a measurement pattern formed on a substrate or line elements forming the measurement pattern will be described.

[0093] First, the function of the measuring device (measurement pattern monitor) will be described. In order to accurately align the substrate 73 and form a device pattern at the desired position, it is important to detect whether there is a change in the characteristic information (shape, structure, physical property value, etc.) of the substrate. If the characteristic change of the substrate exceeds the assumption, the measurement value of the measurement pattern may change, and the alignment accuracy of the substrate or the overlay accuracy of the pattern on the substrate may be reduced. In order to prevent this, the measuring device measures (monitors) the measurement pattern or the characteristics of the pattern and detects whether there is an abnormality in the substrate. When the measuring device detects an abnormality in the substrate, it can issue a warning or an error notification.

[0094] Note that the measurement pattern formed on the substrate in this embodiment is not limited to the alignment pattern or the overlay measurement pattern, and may be a device pattern, for example.

[0095] Will refer to Figure 10 The measurement process according to the second embodiment will be described. The difference between the second embodiment and the first embodiment lies in acquiring signal information from the measurement pattern formed on the substrate, and performing comparison and determination. This will be described in detail. The remaining configuration is the same as that of the first embodiment, and its description will be omitted. Any matters not mentioned here can be handled in accordance with the first embodiment. Figure 10 Steps S1001 to S1006 shown in FIG. Figure 5 Steps S501 to S506 shown in FIG are the same, and their description will be omitted here.

[0096] In step S1006, the controller 11 obtains signal information from the measurement pattern 72, obtains a difference (pattern quality) from the reference data, and determines whether the difference is less than an allowable value. Data based on previously acquired characteristic information or positional information of multiple substrates can be used as the reference data. The allowable value can be set based on a previously acquired amount of variation among the multiple substrates or a desired substrate shape (grid distortion) to achieve the desired overlay.

[0097] In the measurement pattern monitor according to the second embodiment, the measurement processing condition determination method is different from that of the first embodiment. In order to set the measurement processing conditions for accurately detecting changes in the characteristics of the substrate, it is preferable that the signal information to be acquired changes sensitively with respect to the changes in the characteristics of the substrate. In the measurement processing condition determination method according to this embodiment, the measurement processing conditions are set so as to maximize the asymmetry or contrast change of the measurement signal in multiple sample areas on the substrate. Here, the measurement processing conditions can be a measurement parameter, a processing area, or a weight coefficient for each line element in the multiple line elements forming the measurement pattern. The measurement processing conditions can be selected so that the sensitivity of the indication measurement value to the change in the measurement parameter becomes greater.

[0098] The obtained pattern quality or grid distortion can be transmitted (feedback) to a device performing a known process (oxidation, film formation, deposition, doping, planarization, resist removal, etc.) via, for example, an online host, for quality management.

[0099] As described above, in the second embodiment, light from a pattern formed on a substrate is imaged, the relationship between measurement parameters and signal information is acquired, and measurement processing conditions sensitive to changes in substrate characteristics are determined based on this acquired relationship. This allows for highly accurate detection of pattern quality.

[0100] <Third embodiment>

[0101] As a third embodiment, a measurement method for performing position measurement of a substrate and quality monitoring of a pattern formed on the substrate will be described.

[0102] First, the function of the measuring device (measurement pattern monitor) will be described. As described above, in order to accurately align the substrate 73 and form the device pattern at the desired position, it is important to:

[0103] Selecting measurement parameter values ​​that minimize measurement errors associated with process variations, and

[0104] Detect whether there is any change in the characteristic information (shape, structure, physical property values, etc.) of the substrate.

[0105] Will refer to Figure 11 The measurement method according to the third embodiment will be described. The third embodiment differs from the first and second embodiments in that precise alignment measurement and measurement pattern monitoring are performed simultaneously, and this will be described in detail. The remaining configuration is the same as that of the first and second embodiments, and its description will be omitted here. Any matters not mentioned here can be applied to the first and second embodiments.

[0106] Figure 11 is a diagram showing a measurement sequence according to the third embodiment. Figure 11Steps S1101 to S1105 shown are the same as Figure 5 Steps S501 to S505 are the same, and their description is omitted here.

[0107] In step S1106, the signal information of the measurement pattern 72 is acquired, and the substrate position measurement and the determination of whether the pattern quality falls within the allowable range are performed in parallel. In the third embodiment, it is necessary to set a condition that is insensitive to the change in the characteristics of the substrate and a condition that is sensitive to the change in the characteristics of the substrate as the measurement processing conditions. For example, Figure 12 As shown, processing region 75WC is configured to include only (insensitive) patterns, for which measurement errors associated with process variations are small. On the other hand, processing region 75WC′ is configured to include only (sensitive) patterns, for which measurement errors associated with process variations are large. Thus, using the signal information obtained from processing region 75WC, the position of the measurement pattern can be accurately measured. Using the signal information obtained from processing region 75WC′, the quality of the pattern can be accurately detected.

[0108] As described above, in the third embodiment, light from a pattern formed on a substrate is imaged, the relationship between measurement parameters and signal information is acquired, and based on this acquired relationship, measurement processing conditions sensitive to changes in substrate characteristics and measurement processing conditions insensitive to changes in substrate characteristics are set. This makes it possible to simultaneously and accurately perform substrate position measurement and pattern quality inspection.

[0109] <Fourth embodiment>

[0110] As a fourth embodiment, a measurement method for detecting a measurement error (TIS) derived from a measurement device and a measurement error (WIS) caused by characteristics of a pattern formed on a substrate will be described.

[0111] The TIS and WIS will be described. TIS is an error caused by aberrations of the measurement device and is independent of the substrate's orientation. On the other hand, WIS is a measurement error caused by the shape, structure, and physical property values ​​of the pattern formed on the substrate, and therefore, its sign changes depending on the substrate's orientation. In order to accurately align substrate 73 and form a device pattern in the desired position, it is important to detect changes in TIS and WIS.

[0112] The following will refer to Figure 13 The measurement method according to the fourth embodiment will be described. The fourth embodiment differs from the first embodiment in that the pattern signal information is acquired while the substrate position is changed. This will be described in detail. The remaining configuration is the same as that of the first embodiment, and its description will be omitted here. Any matters not mentioned here can be handled in accordance with the first embodiment.

[0113] Figure 13 is a diagram showing a measurement sequence according to the fourth embodiment. Figure 13 Steps S1301 and S1303 to S1305 shown are the same as Figure 5 Step S501 shown is the same as steps S503 to S505, and their description will be omitted here.

[0114] In step S1302, the controller 11 may acquire signal information of the measurement pattern 72 on the substrate 73 multiple times through the imaging element 75 (imaging unit) while changing at least one measurement parameter. The multiple measurements may include measurements at positions along the rotation direction of the substrate (e.g., at the 0° position and the 180° position of the substrate).

[0115] In step S1306, signal information from the measurement pattern 72 is acquired, at least one of the TIS and WIS is removed, and a difference from the reference data is determined. A determination is then made as to whether the difference meets the tolerance. Pre-acquired characteristic information or positional information for multiple substrates can be used as the reference data. The tolerance can be set based on the variation in the multiple substrates or the desired substrate shape to achieve the desired overlay.

[0116] Next, a TIS / WIS detection operation method according to the fourth embodiment will be described.

[0117] Let M0 and M180 be the measured values ​​obtained by rotating the substrate to 0° and 180° and obtaining the position of the pattern. Furthermore, let TWI0 and TWI180 be the errors that occur due to the interaction between the TIS and WIS and the positional deviation amount Shift during substrate transfer. In this case, the measured values ​​M0 and M180 are given by the following equations:

[0118] M0=Shift+TIS+WIS+TWI0...(6)

[0119] M180=-Shift+TIS-WIS+TWI180...(7)

[0120] To detect TIS, arithmetic processing is performed to remove WIS. Therefore, the measured value MTIS when detecting TIS is given by the following formula:

[0121] MTIS=Shift+TIS+(TWI0-TWI180) / 2...(8)

[0122] According to equation (8), TIS can be detected more accurately compared with equations (6) and (7).

[0123] On the other hand, in order to detect WIS, arithmetic processing is performed to remove TIS. Therefore, the measured value MWIS when detecting WIS is given by the following formula:

[0124] MWIS=Shift+WIS+(TWI0-TWI180) / 2...(9)

[0125] According to equation (9), WIS can be detected more accurately compared with equations (6) and (7).

[0126] As described above, in the fourth embodiment, light from a pattern formed on a substrate is imaged, the relationship between measurement parameters and signal information is acquired, and based on this acquired relationship, measurement processing conditions sensitive to changes in substrate characteristics are set. Furthermore, signal information at different substrate positions is mathematically processed, allowing for precise detection of TIS and WIS.

[0127] <Embodiment of Lithographic Apparatus Including Measurement Device>

[0128] The following describes a lithography apparatus incorporating the above-mentioned measurement apparatus. The lithography apparatus may be an apparatus for transferring a pattern onto a substrate, such as an exposure apparatus, an imprint apparatus, or an electron beam drawing apparatus. Figure 14 1 is a schematic diagram showing the configuration of an exposure apparatus EXA as an example of a photolithography apparatus. The exposure apparatus EXA is a photolithography apparatus used in a photolithography process as a manufacturing process for an article or device (such as a semiconductor device or a liquid crystal display device), and forms a pattern on a substrate 83. The exposure apparatus EXA exposes the substrate 83 via a reticle 31 serving as a master, thereby transferring the pattern of the reticle 31 to the substrate 83. In this embodiment, the exposure apparatus EXA adopts a step-and-scan method, but it may also adopt a step-and-repeat method or other exposure methods.

[0129] like Figure 14 As shown, the exposure apparatus EXA includes an illumination optical system 801 , a reticle stage RS that holds the reticle 31 , a projection optical system 32 , a substrate stage WS that holds the substrate 83 , a position measuring device 550 , and a controller 1200 .

[0130] The illumination optical system 801 is an optical system that illuminates the illuminated surface using light from the light source unit 800. The light source unit 800 includes, for example, a laser. Examples of lasers include Arf excimer lasers with a wavelength of approximately 193 nm, KrF excimer lasers with a wavelength of approximately 248 nm, and the like, but the type of light source is not limited to excimer lasers. For example, the light source unit 800 can use an F2 laser with a wavelength of approximately 157 nm or extreme ultraviolet (EUV) light with a wavelength of less than or equal to 20 nm as a light source.

[0131] In this embodiment, the illumination optical system 801 shapes the light from the light source unit 800 into slit light having a predetermined shape suitable for exposure, and illuminates the reticle 31 .

[0132] The illumination optical system 801 has a function of uniformly illuminating the reticle 31 and a polarized illumination function. The illumination optical system 801 includes, for example, lenses, mirrors, an optical integrator, a stop, etc., and is formed by arranging a condenser lens, a fly-eye lens, an aperture stop, a condenser lens, a slit, and an imaging optical system in this order.

[0133] The mask 31 is formed of, for example, quartz.

[0134] The reticle 31 is formed with a pattern (circuit pattern) to be transferred to the substrate 83 .

[0135] The reticle stage RS holds the reticle 31 via a reticle chuck (not shown) and is connected to a reticle drive mechanism (not shown). The reticle drive mechanism includes a linear motor and the like, and can move the reticle 31 held by the reticle stage RS by driving the reticle stage RS in the X, Y, and Z directions, as well as in rotational directions about the respective axes. Note that the position of the reticle 31 is measured by a reticle position measurement unit (not shown) of an oblique-incidence light type, and the reticle 31 is arranged at a predetermined position via the reticle stage RS.

[0136] The projection optical system 32 has the function of imaging light from the object plane onto the image plane. In this embodiment, the projection optical system 32 projects light (diffracted light) that has passed through the pattern of the reticle 31 onto the substrate 83, thereby forming an image of the pattern of the reticle 31 on the substrate. As the projection optical system 32, an optical system formed by multiple lens elements, an optical system including multiple lens elements and at least one concave mirror (catadioptric optical system), an optical system including multiple lens elements and at least one diffractive optical element such as a kinoform, etc. can be used.

[0137] A photoresist is applied onto the substrate 83. The substrate 83 is a processing target object to which the pattern of the reticle 31 is transferred, and includes a wafer, a liquid crystal substrate, another processing target substrate, or the like.

[0138] The substrate stage WS holds the substrate 83 via a substrate chuck (not shown) and is connected to a substrate drive mechanism (not shown). The substrate drive mechanism is a positioning mechanism that positions the substrate 83 based on the position of the mark measured using the position measurement device 550. The substrate drive mechanism includes a linear motor, etc., and can move the substrate 83 held by the substrate stage WS by driving the substrate stage WS in the X direction, Y direction, Z direction, and rotational directions around each axis. In addition, a reference plate 39 is provided on the substrate stage WS.

[0139] For example, the position of the reticle stage RS and the position of the substrate stage WS are monitored by a 6-axis laser interferometer 91 or the like, and are driven at a constant speed ratio under the control of the controller 1200 .

[0140] The controller 1200 is formed of a computer (information processing device) including a CPU, a memory, and the like, and operates the exposure apparatus EXA by comprehensively controlling the respective units of the exposure apparatus EXA according to a program stored in a storage unit, for example.

[0141] The controller 1200 controls an exposure process for transferring the pattern of the reticle 31 to the substrate 83 by exposing the substrate 83 through the reticle 31. Furthermore, in the present embodiment, the controller 1200 controls a measurement process in the position measuring device 550 and a correction process (arithmetic processing) of a measurement value obtained by the position measuring device 550. Thus, the controller 1200 also functions as a part of the position measuring device 550.

[0142] In the exposure apparatus EXA, light (diffracted light) that has passed through the reticle 31 is projected onto the substrate 83 via the projection optical system 32. The reticle 31 and the substrate 83 are arranged in an optically conjugate relationship. By scanning the reticle 31 and the substrate 83 at a speed ratio of the reduction ratio of the projection optical system 32, the pattern of the reticle 31 is transferred to the substrate 83.

[0143] The position measurement device 550 is used to measure the position of a target object. In this embodiment, the position measurement device 550 measures the position of a mark 82 (e.g., an alignment mark) provided on the substrate 83. The wavelength variable unit 540 is composed of a wavelength variable element and a holding member. The controller drives the wavelength variable unit 540 in the X direction using a drive mechanism (not shown).

[0144] Reference Figure 15 , a sequence of exposure processing for transferring the pattern of the reticle 31 onto the substrate 83 by exposing the substrate 83 through the reticle 31 will be described. As described above, the exposure processing is performed by the controller 1200 that comprehensively controls the respective units of the exposure apparatus EXA.

[0145] In step S101, the substrate 83 is loaded into the exposure device EXA. In step S102, the surface (height) of the substrate 83 is detected by a shape measuring device (not shown) to measure the surface shape of the entire substrate 83.

[0146] In step S103, calibration is performed. More specifically, based on the designed coordinate position of the fiducial mark provided on the reference plate 39 in the stage coordinate system, the substrate stage WS is driven to position the fiducial mark on the optical axis of the position measurement device 550. The positional offset of the fiducial mark relative to the optical axis of the position measurement device 550 is then measured, and based on this offset, the stage coordinate system is reset so that the origin of the stage coordinate system coincides with the optical axis of the position measurement device 550. Next, based on the designed positional relationship between the optical axis of the position measurement device 550 and the optical axis of the projection optical system 32, the substrate stage WS is driven to position the fiducial mark on the optical axis of the exposure light. The positional offset of the fiducial mark relative to the optical axis of the exposure light is then measured via the projection optical system 32 using a through-the-lens (TTL) measurement system.

[0147] In step S104, based on the calibration result obtained in step S103, a baseline is determined between the optical axis of the position measuring device 550 and the optical axis of the projection optical system 32. In step S105, the position measuring device 550 measures the position of the mark 82 provided on the substrate 83.

[0148] In step S106, global alignment is performed. More specifically, based on the measurement results obtained in step S105, the offset, magnification, and rotation relative to the arrangement of the shot areas on substrate 83 are calculated, and the regularity of the arrangement of the shot areas is determined. Then, a correction coefficient is obtained based on the regularity of the arrangement of the shot areas and the baseline, and the substrate 83 and the reticle 31 (exposure light) are aligned based on the correction coefficient.

[0149] In step S107, the substrate 83 is exposed while the reticle 31 and the substrate 83 are scanned in the scanning direction (Y direction). At this time, based on the surface shape of the substrate 83 measured by the shape measuring device, the substrate stage WS is driven in the Z direction and the tilt direction to sequentially adjust the surface of the substrate 83 to the image plane of the projection optical system 32.

[0150] In step S108, it is determined whether the exposure of all shot areas of the substrate 83 has been completed (i.e., whether there are no unexposed shot areas). If the exposure of all shot areas of the substrate 83 has not been completed, the process returns to step S107, and steps S107 and S108 are repeated until the exposure of all shot areas is completed. On the other hand, if the exposure of all shot areas of the substrate 83 has been completed, the process proceeds to step S109, and the substrate 83 is unloaded from the exposure device EXA.

[0151] In this embodiment, the position of the mark 82 is measured using each of a plurality of different measurement parameters, and the sensitivity of each measurement value corresponding to a change in the measurement parameter is calculated for at least two or more measurement parameters. The measurement parameter used for the measurement is determined based on the sensitivity. This reduces errors in alignment measurement and enables precise alignment. Thus, this embodiment can provide a position measurement device capable of quickly and accurately measuring the position of a pattern on a substrate.

[0152] <Example of the method for manufacturing an article>

[0153] An article manufacturing method for manufacturing an article by using the above-mentioned lithography apparatus will be described exemplarily. The article manufacturing method is applicable to, for example, manufacturing articles such as devices (semiconductor devices, magnetic storage media, liquid crystal display devices, etc.). The manufacturing method includes the steps of exposing a substrate to which a photosensitive agent is applied (forming a pattern on a substrate) by using an exposure device EXA, and developing the exposed substrate (processing the substrate). In addition, the manufacturing method may include other well-known steps (oxidation, film formation, deposition, doping, flattening, etching, resist removal, cutting, bonding, packaging, etc.). The article manufacturing method of this embodiment is more advantageous than the conventional method in at least one of the performance, quality, productivity and production cost of the article. Note that the above-mentioned article manufacturing method can be performed by using a lithography device such as an imprinting device or a drawing device.

[0154] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A measurement method comprising: a preliminary measurement step of performing preliminary measurement for obtaining signal information obtained by detecting a plurality of targets formed on the substrate using measurement light a plurality of times while changing a parameter value of a measurement parameter; an acquisition step of acquiring a relationship between a parameter value and the signal information based on results of multiple preliminary measurements; a determining step of determining, based on the acquired relationship, a target among the plurality of targets for which a primary measurement should be performed; as well as The main measurement step is to perform main measurement on the determined target.

2. The measurement method according to claim 1, wherein: The measurement parameters include at least one of a central wavelength of the measurement light, a bandwidth of wavelengths, a σ value, and polarization properties in an optical path of a measurement device used for performing preliminary measurement and main measurement.

3. The measurement method according to claim 2, wherein: The signal information is at least one of contrast, signal strength information, and position information of the plurality of targets.

4. The measurement method according to claim 3, wherein: The plurality of targets are each a pattern formed by a plurality of line elements, The measurement parameter is the central wavelength of the measurement light illuminating the pattern, The signal information is the contrast of each line element in the plurality of line elements, In the acquisition step, the relationship between the central wavelength and the contrast is acquired for each of the plurality of line elements, and In the determining step, line elements of the plurality of line elements, the line elements having a maximum value of contrast in the relationship being smaller than a threshold value, are excluded from the target of the main measurement.

5. The measurement method according to claim 2, wherein: The plurality of targets are patterns each formed of a plurality of line elements and are arranged in respective shot regions among a plurality of predetermined shot regions set as sample region candidates on the substrate, The measurement parameter is the central wavelength of the measurement light illuminating the pattern, The signal information is the asymmetry of the measurement signal, In the acquisition step, the relationship between the central wavelength and the asymmetry of the measurement signal is acquired for each of the plurality of predetermined projection areas, and In the determining step, a projection region in which a minimum value of asymmetry in the relationship exceeds a threshold value among the plurality of predetermined projection regions is excluded from the sample region candidates. The measurement method according to claim 3 , wherein: The target is a pattern formed by a plurality of line elements, and The determining step includes obtaining a weight coefficient when indicating the position of the pattern by a weighted average of positions of the plurality of line elements.

7. The measurement method according to claim 3, wherein: The target is a pattern formed by a plurality of line elements, and The determining step includes setting a processing area for each of the plurality of line elements, and determining a weight coefficient for each processing area based on overlay measurement values ​​of a plurality of projection areas on the substrate.

8. The measurement method according to claim 4, wherein: The pattern formed by the plurality of line elements is a line-space pattern having gaps between adjacent line elements.

9. The measurement method according to claim 1, wherein: The measurement parameter includes the position of the substrate in a rotational direction.

10. The measurement method according to claim 9, wherein: The performing the main measurement includes detecting at least one of a measurement error derived from a measurement device that performs the preliminary measurement and the main measurement and a measurement error caused by characteristics of a pattern formed on the substrate.

11. A method for manufacturing an article, comprising: The measuring method according to any one of claims 1 to 10 measures a position of a target on a substrate, and transfers a pattern onto the substrate based on the position of the target; as well as The article is obtained by processing the substrate to which the pattern is transferred.

12. A measuring device comprising: Measuring unit; as well as controller, Wherein, the controller is constructed as follows: controlling the measurement unit so that preliminary measurement for obtaining signal information obtained by detecting a plurality of targets formed on a substrate using measurement light is performed a plurality of times while changing a parameter value of a measurement parameter, Based on the results of the preliminary measurements performed multiple times, the relationship between the parameter value and the signal information is obtained, Based on the acquired relationship, determining a target among the plurality of targets for which a main measurement should be performed, and The measuring unit is controlled to perform main measurement on the determined target.

13. A lithographic apparatus comprising: The measuring device according to claim 12, which is configured to measure the position of a mark provided on a substrate; as well as a positioning mechanism configured to position the substrate based on a position of a mark measured using the measuring device, The photolithography device is configured to transfer a pattern of the substrate.

14. A method of manufacturing an article, comprising: transferring the pattern onto a substrate using the lithography apparatus according to claim 13; as well as The article is obtained by processing the substrate to which the pattern is transferred.

Images