Determination method, lithography method, article manufacturing method, positioning device, and lithography device.

Abstract

This invention provides a technology that is advantageous for efficiently determining the correction value applied to the measurement results of a measurement unit that measures the surface height of a substrate, using other measurement units. [Solution] A determination method for determining a correction value to be applied to the measurement result of a first measurement unit that measures the surface height of a substrate, using a second measurement unit that measures the surface height of the substrate, includes: a selection step of identifying two or more measurement points on the substrate where the surface state of the substrate is constant, from among a plurality of measurement points on the substrate whose surface height is measured by the first measurement unit, based on configuration information indicating the configuration of the substrate; a measurement step of measuring the surface height of a representative measurement point among the two or more measurement points using the first measurement unit and the second measurement unit; and a determination step of determining the correction value to be used in common at the two or more measurement points, based on the measurement results of the first measurement unit and the second measurement unit for the representative measurement point.

Description

[[Technical Field]]

[0001] The present invention relates to a determination method, a lithography method, an article manufacturing method, a positioning apparatus, and a lithography apparatus. [[Background Art]]

[0002] Patent Document 1 describes a lithography projection apparatus including, as sensors for measuring the surface height of a substrate, a first sensor that is a process-independent sensor such as an air micrometer, and a second sensor that is a process-dependent sensor such as an optical sensor or a capacitive sensor. A measurement value obtained by the second sensor may have a process-dependent offset error (PDOE). Therefore, in Patent Document 1, the surface height is measured by the first and second sensors for each of a plurality of measurement positions on the substrate, and a map indicating the PDOE of the second sensor is created based on the measurement values of the first and second sensors obtained for each measurement position. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Patent No. 4654201 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] In measurement by a sensor such as an air micrometer, a certain amount of time is required until the pressure value and the flow rate value stabilize, so the measurement time is longer compared to an optical sensor or a capacitive sensor. Therefore, as described in Patent Document 1, when the surface height is measured by a sensor such as an air micrometer for all of the plurality of measurement positions on the substrate, this may be disadvantageous in terms of productivity (throughput).

[0005] Accordingly, an object of the present invention is to provide an advantageous technique for efficiently determining a correction value to be applied to a measurement result of a measurement unit that measures the surface height of a substrate using another measurement unit. [Means for solving the problem]

[0006] To achieve the above objective, a determination method as one aspect of the present invention is a determination method for determining a correction value to be applied to the measurement result of a first measurement unit that measures the surface height of a substrate, using a second measurement unit that measures the surface height of the substrate, and is characterized by comprising: a selection step of identifying two or more measurement points from among a plurality of measurement points on the substrate whose surface height is measured by the first measurement unit, based on configuration information indicating the configuration of the substrate, where the surface state of the substrate is constant; a measurement step of measuring the surface height of a representative measurement point among the two or more measurement points using the first measurement unit and the second measurement unit; and a determination step of determining the correction value to be used in common at the two or more measurement points based on the measurement results of the first measurement unit and the second measurement unit for the representative measurement point.

[0007] Further objects or other aspects of the present invention will be revealed by preferred embodiments described below with reference to the accompanying drawings. [Effects of the Invention]

[0008] According to the present invention, for example, it is possible to provide an advantageous technique for efficiently determining a correction value applied to the measurement result of a measurement unit that measures the surface height of a substrate, using another measurement unit. [Brief explanation of the drawing]

[0009] [Figure 1] This figure schematically shows an example of the configuration of the exposure apparatus of the first embodiment. [Figure 2A] This diagram schematically shows a first example configuration of an air sensor. [Figure 2B] This diagram schematically shows a second configuration example of the air sensor. [Figure 3] A diagram illustrating the measurement errors that occur in the measurement results of optical measuring instruments. [Figure 4] Flowchart showing the method for determining the correction value in the first embodiment [Figure 5]This figure shows an example of setting representative measurement points in the first embodiment. [Figure 6] This figure shows an example of setting representative measurement points in the first embodiment. [Figure 7] Flowchart showing the exposure process of the first embodiment [Figure 8] This figure shows an example of setting representative measurement points in the second embodiment. [Figure 9] This diagram shows how the surface height of a substrate is measured using an optical measuring instrument and an air sensor. [Figure 10] A diagram showing the layout of multiple shot regions on the substrate and the position of the measurement points in each shot region. [Modes for carrying out the invention]

[0010] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0011] The lithography apparatus according to the present invention is an apparatus for forming a pattern on a substrate. Examples of lithography apparatuses include an exposure apparatus that exposes a substrate to transfer a pattern from a master plate (mask) onto the substrate, and an imprint apparatus that uses a master plate (mold) to form a pattern on an imprint material on a substrate. In the following, an exposure apparatus will be used as an example to explain the lithography apparatus.

[0012] <First Embodiment> A first embodiment of the present invention will now be described. Figure 1 schematically shows an example of the configuration of the exposure apparatus 100 of this embodiment. The exposure apparatus 100 may be configured to expose the substrate 1 by projecting the pattern of the original plate 11 onto the substrate 1 using the projection optical system 13, and including an illumination optical system 12 for illuminating the original plate 11 and a projection optical system 13 for projecting the pattern of the original plate 11 onto the substrate 1 using the projection optical system 13. The exposure apparatus 100 may also include a substrate stage 41 that can hold and move the substrate 1, an optical measuring instrument 21 that measures the surface height of the substrate 1 using light, an air sensor 22 that measures the surface height of the substrate 1 using gas, and a control unit CNT. The substrate stage 41, optical measuring instrument 21, air sensor 22, and control unit CNT may constitute a positioning device for positioning the substrate 1.

[0013] The substrate stage 41 holds the substrate 1 and drives the substrate 1 in the XY direction by moving it on a stage base plate (not shown) in the XY direction. The substrate stage 41 may be configured to drive the substrate 1 not only in the XY direction but also in the six axes (X, Y, Z, θX, θY, θZ). The substrate stage 41 may also be provided with a reference plate 2 having a reference surface. The reference surface of the reference plate 2 is a flat surface, and reference marks whose position is detected by an alignment sensor (not shown) may be provided on this reference surface.

[0014] The position and orientation of the substrate stage 41 are measured by a position measurement system MS and can be controlled by a control unit CNT based on the output of the position measurement system MS. The position measurement system MS comprises multiple position measuring instruments and measures the position and orientation of the substrate stage 41 in terms of six axes (X, Y, Z, θX, θY, θZ). Figure 1 shows two position measuring instruments 42-43 that measure the position of the substrate stage 41 in the Y direction, but in reality, position measuring instruments that measure the position of the substrate stage 41 in the X direction, and position measuring instruments that measure the position of the substrate stage 41 in the Z direction may also be provided. Each position measuring instrument may include, for example, an interferometer, an encoder, or one or more interferometers and one or more encoders.

[0015] The optical measuring instrument 21 is a measuring instrument (first measuring instrument) that irradiates light onto the surface of a substrate 1, receives reflected light from the substrate 1, and measures the surface height of the substrate 1 based on the reflected light. The optical measuring instrument 21 of the present embodiment can be configured as an oblique-incidence measuring instrument that allows light to obliquely enter the surface of the substrate 1. Specifically, the optical measuring instrument 21 may include a light projector 21a that projects patterned light onto the substrate 1, and a light receiver 21b that receives reflected light from the substrate 1. In the optical measuring instrument 21, light is reflected not only by the outermost surface of the substrate 1 but also by the internal structure of the substrate 1 (a structure existing under the outermost surface), so measurement errors depending on the internal structure of the substrate 1 may occur.

[0016] The air sensor 22 is a measuring instrument (second measuring instrument) that measures the surface height of the substrate 1 based on the pressure in a pipeline while discharging (injecting) air (gas) onto the surface of the substrate 1 through the pipeline. The air sensor 22 can be configured to be capable of measuring the surface height of the substrate 1 with nanometer-order resolution or resolution higher than 1 nm. The air discharged from the air sensor 22 only strikes the outermost surface of the substrate 1 and does not enter the interior of the substrate 1, so the measurement result obtained by the air sensor 22 is not affected by the internal structure of the substrate 1. The air sensor 22 is sometimes also referred to as an air gap sensor or an air microsensor.

[0017] The control unit CNT is constituted by, for example, a computer (information processing apparatus) including a processor such as a CPU (Central Processing Unit) and a storage unit such as a memory, and controls each part of the exposure apparatus 100. The control unit CNT may be constituted by, for example, a PLD (abbreviation for Programmable Logic Device) such as an FPGA (abbreviation for Field Programmable Gate Array), or an ASIC (abbreviation for Application Specific Integrated Circuit), or a general-purpose or special-purpose computer embedded with a program, or a combination of all or part of the above.

[0018] Next, an example configuration of the air sensor 22 will be described. Figure 2A schematically shows a first configuration example of the air sensor 22. The air sensor 22 may include a reference nozzle 31 that discharges air through a first conduit C1, a measuring nozzle 32 that discharges air through a second conduit C2, and a differential pressure sensor 33 that detects the difference between the pressure in the first conduit C1 and the pressure in the second conduit C2. Orifices 30 are provided at the air inlet and outlet of each of the reference nozzle 31 and the measuring nozzle 32. Here, the exposure apparatus 100 is provided with a drive mechanism 24 (for example, a lifting mechanism) for moving the air sensor 22, and the height of the air sensor 22 can be adjusted by the drive mechanism 24.

[0019] Air may be supplied to the reference nozzle 31 (first pipeline C1) and the measurement nozzle 32 (second pipeline C2) from the mass flow controller 36 via a sensor 35 such as a pressure gauge or flow meter. Air is supplied to the mass flow controller 36 from a gas supply source 39 via a valve 38 and a filter 37. The valve 38 may be provided to turn the supply of air from the gas supply source 39 to the mass flow controller 36 on / off. The filter 37 may be provided to supply clean air from the gas supply source 39 to the mass flow controller 36. In addition, the output of the differential pressure sensor 33 is transmitted to the processor 34, which converts the output of the differential pressure sensor 33 (i.e., the difference between the pressure in the first pipeline C1 and the pressure in the second pipeline C2) into height information.

[0020] The mass flow controller 36 supplies air with a constant pressure and flow rate to the reference nozzle 31 and the measurement nozzle 32. Specifically, the mass flow controller 36 may operate to maintain the pressure on the outlet side of the mass flow controller 36 at a predetermined pressure (e.g., 70 kPa ± 0.01 kPa) based on the output of the sensor 35. The diameter of the orifice 30 provided in the reference nozzle 31 and the measurement nozzle 32 may be in the range of, for example, 0.1 to 0.2 mm. The orifice 30 acts as a resistance to the airflow, so that the pressure in the first conduit C1 of the reference nozzle 31 can be maintained at a constant level. On the other hand, the pressure in the second conduit C2 of the measurement nozzle 32 is a value that depends on the distance between the measurement nozzle 32 and the surface to be measured (e.g., the surface of the substrate 1). In other words, the pressure in the second conduit C2 increases as the distance between the measurement nozzle 32 and the surface to be measured decreases, and the pressure in the second conduit C2 decreases as the distance increases.

[0021] The differential pressure sensor 33 is supplied with the pressure in the first conduit C1 of the reference nozzle 31 and the pressure in the second conduit C2 of the measuring nozzle 32. In other words, the differential pressure sensor 33 is supplied with a differential pressure corresponding to the distance between the measuring nozzle 32 and the surface to be measured (in this embodiment, the surface of the substrate 1). The processor 34 converts the output of the differential pressure sensor 33 into height information and provides this height information to the control unit CNT. In this way, the air sensor 22 measures the height of the surface to be measured by discharging air onto the surface to be measured, which is the outermost surface, so measurement errors caused by internal structures that may exist below the surface to be measured do not occur.

[0022] Figure 2B schematically shows a second configuration example of the air sensor 22. In the second configuration example, a first differential pressure sensor 33A and a second differential pressure sensor 33B are provided instead of the differential pressure sensor 33 of the first configuration example. The first differential pressure sensor 33A detects the difference between the pressure in the first conduit C1 of the reference nozzle 31 and the pressure in the second conduit 72 of the measurement nozzle 32. Similarly, the second differential pressure sensor 33B detects the difference between the pressure in the first conduit C1 of the reference nozzle 31 and the pressure in the second conduit C2 of the measurement nozzle 32. The first differential pressure sensor 33A and the second differential pressure sensor 33B have different sensitivities (and measurement ranges). The processor 34 can convert the output of the first differential pressure sensor 33A into height information and can also convert the output of the second differential pressure sensor 33B into height information.

[0023] Next, we will explain the measurement errors (measurement deception) that occur in the measurement results of the optical measuring instrument 21. Figure 3 is a diagram illustrating the measurement errors that occur in the measurement results of the optical measuring instrument 21. The substrate 1 may have multiple layers 52 to 54 on a base material (not shown) made of a semiconductor, and on top of that, a resist 51 that constitutes the outermost surface. At the submicrometer level, the outermost surface of the substrate 1 has an uneven shape before the resist 51 is applied, and the outermost surface of the substrate 1 after the resist 51 is applied (i.e., the surface of the resist 51) also has an uneven shape.

[0024] In the exposure apparatus 100, the position of the outermost surface of the resist 51, which is the surface of the substrate 1 that should coincide with the image plane of the projection optical system 13, should be measured by the optical measuring instrument 21. However, in the optical measuring instrument 21, a portion of the light projected onto the substrate 1 by the light projector 21a may pass through the resist 51 and reach at least one of the multiple layers 52-54 beneath the resist 51, as shown by the dashed line in Figure 3. Then, the light reflected by at least one of the multiple layers 52-54 may enter the light receiver 21b. In this way, the light reflected from the outermost surface of the substrate 1 and the light reflected from the layer below interfere with each other and enter the light receiver 21b, which can cause measurement errors (measurement deception) in the measurement results of the optical measuring instrument 21. Note that if the multiple layers 52-54 are flat and the thickness and refractive index of the resist 51 are known, it may be possible to calculate the amount of measurement error (amount of measurement deception). However, in reality, since the surfaces of the multiple layers 52-54 and the resist 51 are not flat, it is not practical to calculate the amount of measurement error.

[0025] Therefore, in the exposure apparatus 100, a correction value (hereinafter sometimes simply referred to as the correction value) for correcting measurement errors that occur in the measurement results of the optical measuring instrument 21 is determined using the air sensor 22. For example, the correction value for a given location can be determined based on the difference in the results of measuring the surface height of the same location on the substrate 1 using the optical measuring instrument 21 and the air sensor 22.

[0026] Conventionally, for each of the multiple measurement points on the substrate 1 where the surface height should be measured by the optical measuring instrument 21, the surface height was measured using both the optical measuring instrument 21 and the air sensor 22, and a correction value for each measurement point was individually determined based on the difference between these measurement results. However, while the measurement time for one measurement point using the optical measuring instrument 21 is only a few milliseconds, the measurement time for one measurement point using the air sensor 22 is only about 300 milliseconds, which is significantly longer than that of the optical measuring instrument 21. Therefore, in order to determine the correction value for each of the multiple measurement points on the substrate 1, measuring the surface height using the air sensor 22 for all of those measurement points can be disadvantageous in terms of productivity (throughput).

[0027] Therefore, in this embodiment, from among a plurality of measurement points on the substrate 1 whose surface height should be measured by the optical measuring instrument 21, two or more measurement points where the surface state of the substrate 1 is constant (uniform, the same) are identified based on configuration information indicating the configuration of the substrate 1. Then, at least one of the identified two or more measurement points is designated as a representative measurement point, and the surface height of the representative measurement point is measured by the optical measuring instrument 21 and the air sensor 22. Based on these measurement results, a correction value to be used commonly for the two or more measurement points is determined. This reduces the number of measurement points measured by the air sensor 22, thereby reducing the time required to determine the correction value and improving productivity.

[0028] Figure 4 is a flowchart illustrating a method for determining correction values ​​applied to the measurement results of the optical measuring instrument 21. The flowchart in Figure 4 may be executed by the control unit CNT. Here, the substrate 1 includes a plurality of shot regions on which a pattern is formed by the exposure apparatus 100, and a plurality of measurement points on the substrate 1 may be arranged on the substrate 1 such that each of the plurality of shot regions includes at least one measurement point.

[0029] In step S11, the control unit CNT acquires configuration information indicating the configuration of the substrate 1. The configuration information may include, for example, at least one of the following: process information indicating the process conditions of the substrate 1, pattern information indicating the layout of the patterns formed on the substrate 1, and step information indicating the arrangement of steps on the substrate 1. The process information may include, for example, information indicating the conditions of processes performed on the substrate 1 so far, and may include information indicating the method of supplying the resist (photosensitive material) that constitutes the outermost surface of the substrate 1. The pattern information may include, for example, information indicating the layout of multiple shot areas on the substrate 1, and / or information indicating the configuration of the pattern in one shot area. The step information may include information indicating the arrangement of steps that have occurred on the substrate 1 (or one shot area) before the resist is applied. The pattern information and step information may also be design data (e.g., CAD data) that specifies the arrangement / configuration of the patterns to be formed on the substrate 1.

[0030] In step S12, the control unit CNT identifies two or more measurement points on the substrate 1 from among multiple measurement points on the substrate 1, based on the configuration information acquired in step S11, where the surface state of the substrate 1 is constant (e.g., the same). "The surface state of the substrate 1 is constant" can be understood as the difference in surface state between two or more measurement points being within an acceptable range. For example, consider a case where the process information as configuration information includes the method of supplying resist onto the substrate 1 as the spin coating method. The spin coating method is a method of coating the substrate 1 by dropping resist liquid near the center of gravity on the substrate 1 and rotating the substrate 1 at high speed, thereby using centrifugal force. When resist is coated onto the substrate 1 using the spin coating method, the film thickness of the resist is distributed in a concentric pattern. That is, among multiple measurement points on the substrate 1, the surface state of the substrate 1 tends to be constant at two or more measurement points located on a circular line centered on the center of gravity of the substrate 1 (e.g., the rotation center of the substrate 1 in the spin coating method). Therefore, based on the configuration information (process information), the control unit CNT can identify two or more measurement points on the substrate 1 where the surface state of the substrate 1 is constant, from among multiple measurement points on the substrate 1.

[0031] In step S13, the control unit CNT selects (sets, determines) a representative measurement point from among the two or more measurement points identified in step S12, assuming that the surface state of the substrate 1 is constant, to measure the surface height using the air sensor 22. In this embodiment, the representative measurement point selected from among the two or more measurement points is one, but it may be two or more. If two or more representative measurement points are selected, the number of representative measurement points is less than the number of measurement points identified in step S12, assuming that the surface state of the substrate 1 is constant.

[0032] Figure 5 shows an example of setting representative measurement points 9 for a substrate 1 coated with resist using the spin-coating method. The control unit CNT sets up a plurality of circular lines 10a centered on the centroid (reference point) of the substrate 1 based on configuration information (e.g., process information) (step S12). The plurality of circular lines 10a can be concentric circles. Then, for each of the plurality of circular lines 10a, the control unit CNT identifies two or more measurement points located on the circular line 10a and selects a representative measurement point 9 from among these two or more measurement points (step S13). In the example in Figure 5, one representative measurement point 9 is selected (set) for each circular line 10a, but two or more representative measurement points 9 may be selected for each circular line 10a. Also, in the example in Figure 5, the representative measurement points 9 set for each circular line 10a are arranged linearly along the radial direction, but as shown in Figure 6, the representative measurement points 9 set for each circular line 10a do not have to be arranged linearly.

[0033] In step S14, the control unit CNT measures the surface height of the representative measurement point 9 using the optical measuring instrument 21 and the air sensor 22. In the example shown in Figures 5 and 6, the control unit CNT measures the surface height of the representative measurement point 9 set for each circular line 10a using the optical measuring instrument 21 and the air sensor 22.

[0034] In step S15, the control unit CNT determines a correction value to be applied to the detection result of the optical measuring instrument 21 based on the measurement results of the optical measuring instrument 21 and the air sensor 22 for the representative measurement point 9. For example, the control unit CNT determines the correction value based on the difference between the measurement result of the optical measuring instrument 21 and the measurement result of the air sensor 22 for the representative measurement point 9. The correction value determined using one representative measurement point 9 is used in common for two or more measurement points on the line (on the circular line 10a) where the representative measurement point 9 is located. If multiple circular lines 10a are set up as shown in Figures 5 and 6, the correction value is determined for each circular line 10a using the representative measurement point 9.

[0035] Here, the correction value applied to a measurement point located between two radially adjacent circular lines 10a is determined (calculated) based on the correction value determined for each of the two radially adjacent circular lines 10a. Specifically, let α1 and α2 be the correction values ​​determined for each of the two radially adjacent circular lines 10a. In this case, the correction value applied to a measurement point located between the two circular lines 10a can be determined (calculated) by performing linear interpolation or approximation with a polynomial of degree two or higher on the correction values ​​α1 and α2.

[0036] Furthermore, if two or more representative measurement points 9 are set on a single circular line 10a, correction values ​​may be determined for each of these two or more representative measurement points 9. For example, let β1 and β2 be the correction values ​​determined for two or more representative measurement points 9 on a single circular line 10a. In this case, the average value of correction value β1 and correction value β2 may be used as the correction value applied to each measurement point on the single circular line 10a, or the correction value (β1 or β2) of the closest representative measurement point 9 among the two or more representative measurement points 9 may be used.

[0037] Next, the operation of the exposure apparatus 100, that is, the exposure process (exposure method, lithography method), will be described. Figure 7 is a flowchart of the exposure process in this embodiment. The flowchart in Figure 7 can be executed by the control unit CNT.

[0038] In step S21, the control unit CNT uses a transport hand (not shown) to load the substrate 1 onto the substrate stage 41 and holds the substrate 1 on the substrate stage 41. Next, in step S22, the control unit CNT performs pre-measurement and correction for global alignment in step S26, which will be described later (pre-alignment). Specifically, the control unit CNT uses a low-magnification alignment scope (not shown) to measure and correct the amount of deviation in the position and rotation of the substrate 1 so that the marks on the substrate 1 are within the field of view of a high-magnification alignment scope (not shown) used for global alignment.

[0039] In step S23, the control unit CNT measures the surface height of each of the multiple measurement points on the substrate 1 using the optical measuring instrument 21, and calculates and corrects the overall tilt of the substrate 1 based on the measurement results (global tilt). Next, in step S24, the control unit CNT performs pre-adjustments for measuring the surface height of the substrate 1 with the optical measuring instrument 21 during scanning exposure in step S27, which will be described later. Pre-adjustments may include, for example, calibration of the optical measuring instrument 21 (such as adjusting the light intensity of the light source) and storage of pattern step differences in each shot area of ​​the substrate 1.

[0040] In step S25, the control unit CNT determines a correction value to correct for measurement errors occurring in the measurement results of the optical measuring instrument 21. The correction value is determined for each of the multiple measurement points on the substrate 1 using the air sensor 22 according to the determination method described above (see Figure 4). The multiple measurement points can be arranged on the substrate 1 such that at least one measurement point is included in each of the multiple shot regions on the substrate 1. Note that the determination of the correction value in step S25 may be performed for each substrate 1, or it may be performed for each lot containing multiple substrates 1. For example, the determination of the correction value in step S25 may be performed for the first substrate 1 in the lot.

[0041] In step S26, the control unit CNT measures the alignment marks on the substrate 1 using a high-magnification field-of-view alignment scope (not shown), calculates the total misalignment of the substrate 1 and the common misalignment for each shot area, and corrects them (global alignment). The misalignment may also include rotational misalignment. Here, in order to accurately measure the alignment marks, the substrate 1 should be positioned at the position (height) where the contrast of the alignment marks is at its best. An optical measuring instrument 21 and a high-magnification field-of-view alignment scope can be used to measure this best contrast position. Specifically, the control unit CNT moves the substrate stage 41 to a predetermined height (Z-axis direction) and measures the contrast using the high-magnification field-of-view alignment scope and the surface height using the optical measuring instrument 21. These measurements are repeated while changing the height of the substrate stage 41 (substrate 1). At this time, the control unit CNT stores the surface height measurement results and the contrast measurement results corresponding to each surface height in association. Then, the control unit CNT determines the surface height with the highest contrast based on the multiple contrast measurement results obtained, and sets it as the best contrast position (height).

[0042] In step S27, the control unit CNT performs scanning exposure of the shot area to be exposed, while having the optical measuring instrument 21 measure the surface positions of the measurement points included in the shot area to be exposed. In this process, the control unit CNT applies the correction value determined in step S25 to the measurement result of the optical measuring instrument 21 during the exposure of the shot area, and drives the substrate stage 41 so that the surface of the substrate 1 is positioned at the best contrast position based on the value obtained. The scanning exposure in step S27 is performed on all shot areas on the substrate 1. Once scanning exposure is completed for all shot areas, the process proceeds to step S28, where the control unit CNT releases the substrate 1 from the substrate stage 41 and removes the substrate 1 from the substrate stage 41 using a transport hand (not shown). In this way, a series of exposure processes for one substrate 1 is completed.

[0043] As described above, in this embodiment, based on the configuration information, two or more measurement points on the substrate 1 where the surface state of the substrate 1 is constant are identified from among a plurality of measurement points on the substrate 1. Then, the surface height of a representative measurement point 9 among the two or more measurement points is measured by the optical measuring instrument 21 and the air sensor 22, and a correction value to be used in common for the two or more measurement points is determined based on these measurement results. This reduces the number of measurement points measured by the air sensor 22, thereby reducing the time required to determine the correction value and improving productivity.

[0044] In the above embodiment, an optical measuring instrument 21 and an air sensor 22 were given as examples of the first and second measuring units for measuring the surface height of the substrate 1, respectively. However, the first and second measuring units are not limited to the optical measuring instrument 21 and the air sensor 22, as long as they measure the surface height of the substrate 1 in different ways. For example, a capacitive sensor may be used as the first measuring unit instead of the optical measuring instrument 21. As the second measuring unit, a sensor that measures the surface height of the substrate 1 by irradiating light onto the surface of the substrate 1 in a way different from the oblique incidence method may be used instead of the air sensor 22.

[0045] <Second Embodiment> A second embodiment of the present invention will now be described. In the first embodiment described above, an example was described in which measurement points located on a circular line 10a centered on the centroid of the substrate 1 are identified as two or more measurement points where the surface state of the substrate 1 is constant. In this embodiment, another example of identifying two or more measurement points where the surface state of the substrate 1 is constant will be described. Note that this embodiment basically follows the first embodiment, and except for the matters mentioned below, it may follow the first embodiment.

[0046] Figure 8 shows an example of setting a representative measurement point 9 on the substrate 1. As described above using Figure 3, the substrate 1 has multiple layers 52 to 54 and a resist 51 on top of them, and layer 52 may be configured as an uneven pattern structure. In this case, depending on the uneven pattern structure of layer 52, the surface state of the substrate 1 may be constant at two or more measurement points located on lines extending radially from the center of gravity of the substrate 1.

[0047] In this case, the control unit CNT sets radial lines 10b extending radially from the center of gravity of the substrate 1 based on the configuration information (step S12). Then, for each of the multiple radial lines 10b, the control unit CNT identifies two or more measurement points located on the radial line 10b and selects a representative measurement point 9 from among these two or more measurement points (step S13). In the example in Figure 8, one representative measurement point 9 is selected (set) for each radial line 10b, but two or more representative measurement points 9 may be selected for each radial line 10b.

[0048] In this embodiment as well, after setting the representative measurement point 9, the surface height of the representative measurement point 9 is measured by the optical measuring instrument 21 and the air sensor 22, similar to the first embodiment, and a correction value to be used in common at two or more measurement points is determined based on these measurement results. This reduces the number of measurement points measured by the air sensor 22, thereby reducing the time required to determine the correction value and improving productivity.

[0049] <Third Embodiment> A third embodiment of the present invention will now be described. In this embodiment, an example will be described in which a plurality of measurement points on the substrate 1 are set so that the surface height is to be measured by the optical measuring instrument 21. This embodiment basically follows the first embodiment, and can be followed in accordance with the first embodiment except for the matters mentioned below. In addition, in this embodiment, the second embodiment may be applied in addition to the first embodiment, or in place of the first embodiment.

[0050] Figure 9 shows how the surface height of substrate 1 is measured by an optical measuring instrument 21 and an air sensor 22. Substrate 1 may have, for example, multiple layers 52 to 54 on a base (not shown) made of a semiconductor, and a resist 51 forming the outermost surface. Layer 52 may be configured as an uneven pattern structure with relatively large steps (heights), and due to the steps of layer 52, the outermost surface of substrate 1 after the resist 51 is applied (i.e., the surface of the resist 51) also becomes uneven. Note that in Figure 9, the positional relationship between the optical measuring instrument 21 and the air sensor 22 has been changed compared to Figure 1 for the sake of clarity, but this positional relationship may be the same as in Figure 1.

[0051] In the example shown in Figure 9, the surface of the resist 51 is sloped near the edges of the layer 52 (protrusions) having an uneven pattern structure. In this case, if a measurement point is set on the sloped portion of the resist 51 near the edges of the layer 52 (protrusions) having an uneven pattern structure, the light from the optical measuring instrument 21 (projector 21a) will be scattered at the sloped portion, potentially causing measurement errors in the measurement results of the optical measuring instrument 21. Furthermore, even when measuring the measurement point on the sloped portion of the resist 51 using the air sensor 22, the pressure in the second conduit 72 of the measurement nozzle 32 of the air sensor 22 will be affected by the sloped portion, potentially causing measurement errors in the measurement results of the air sensor 22. Therefore, in order to accurately determine the correction value by measuring the surface height of the substrate 1 using the optical measuring instrument 21 and the air sensor 22, it is desirable to set the measurement point so as to avoid the sloped portion of the resist 51.

[0052] In this embodiment, the exposure apparatus 100 (control unit CNT) may have measurement points set on parts of the surface of the substrate 1 other than the inclined portion of the resist 51 (for example, parts with a flat surface), such as the location 61 shown in Figure 9. The measurement points may be set based on configuration information, or based on the results of a prior measurement of the surface height of the substrate 1. The prior measurement of the surface height of the substrate 1 may be performed using the optical measuring instrument 21, or using a measuring instrument located outside the exposure apparatus 100. Furthermore, the measurement points may be set so that at least one measurement point is included in each of the multiple shot regions on the substrate 1.

[0053] Figure 10 shows the layout of multiple shot regions 1a on the substrate 1 and the positions of the measurement points 62 in each shot region 1a. The measurement points 62 may be set in a portion of the resist 51 other than the sloped portion for each shot region 1a. Also, since the layer structure (i.e., the uneven pattern structure) of the substrate 1 is the same for multiple shot regions 1a, the measurement points 62 may be set so that their position on one shot region is the same for multiple shot regions 1a. Here, in Figure 10, one measurement point 62 is provided for each shot region 1a, but two or more measurement points 62 may be provided for each shot region 1a. That is, at least one measurement point 62 may be provided for each shot region 1a. Also, in Figure 10, for the sake of clarity, the measurement points 62 are shown for only a portion of the multiple shot regions 1a, but in reality, measurement points 62 are provided for all of the multiple shot regions 1a.

[0054] In the example shown in Figure 10, as described in the first embodiment, the control unit CNT identifies two or more measurement points 62 on the substrate 1 from among a plurality of measurement points 62, based on the configuration information, where the surface state of the substrate 1 is constant. Then, the surface height of a representative measurement point 9 among the two or more measurement points 62 is measured by the optical measuring instrument 21 and the air sensor 22, and a correction value to be used commonly for the two or more measurement points 62 is determined based on these measurement results. In this embodiment as well, since the number of measurement points measured by the air sensor 22 can be reduced, the time required to determine the correction value can be reduced, and productivity can be improved.

[0055] <Embodiment of Article Manufacturing Method> The article manufacturing method according to an embodiment of the present invention is suitable for manufacturing articles such as microdevices such as semiconductor devices and elements having a microstructure. The article manufacturing method of this embodiment includes a formation step of forming a pattern on a substrate using the above-described lithography apparatus (lithography method), a processing step of processing the substrate on which the pattern was formed in the formation step, and a manufacturing step of manufacturing an article from the substrate processed in the processing step. When the lithography apparatus is configured as an exposure apparatus, the formation step may be a step of forming a latent image pattern on a photosensitive agent coated on a substrate by exposing the substrate using the above-described exposure apparatus (exposure method). In this case, the processing step may include a step of developing the substrate on which the latent image pattern was formed. Furthermore, the article manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method of this embodiment is advantageous compared to conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0056] <Summary of Embodiments> The disclosures herein include at least the following determination methods, lithography methods, article manufacturing methods, positioning devices, and lithography apparatus. (Item 1) A determination method for determining a correction value to be applied to the measurement result of a first measurement unit that measures the surface height of a substrate, using a second measurement unit that measures the surface height of the substrate, A selection step in which, from among a plurality of measurement points on the substrate whose surface height is measured by the first measurement unit, two or more measurement points are identified in which the surface state of the substrate is constant, based on configuration information indicating the configuration of the substrate, A measurement step comprising measuring the surface height of a representative measurement point among the two or more measurement points using the first measurement unit and the second measurement unit, A determination step in which, based on the measurement results of the first measurement unit and the second measurement unit for the representative measurement point, the correction value to be used in common at the two or more measurement points is determined, A determination method characterized by including the following. (Item 2) The determination method according to item 1, characterized in that the first measurement unit and the second measurement unit measure the surface height of the substrate in different ways. (Item 3) The first measurement unit measures the surface height of the substrate using light, The determination method according to item 1 or 2, characterized in that the second measuring unit measures the surface height of the substrate using a gas. (Item 4) The determination method according to item 3, characterized in that the second measuring unit measures the height of the substrate based on the pressure in the pipeline while discharging gas through the pipeline. (Item 5) The determination method according to any one of items 1 to 4, characterized in that the determination step involves determining the correction value based on the difference between the measurement result of the first measurement unit and the measurement result of the second measurement unit for the representative measurement point. (Item 6) The determination method according to any one of items 1 to 5, characterized in that the configuration information includes at least one of the following: information indicating the process conditions of the substrate, information indicating the layout of the pattern formed on the substrate, and information indicating the arrangement of steps on the substrate. (Item 7) The determination method according to any one of items 1 to 6, characterized in that, in the specified step, based on the configuration information, measurement points located on a circular line centered on the center of gravity of the substrate are identified as two or more measurement points where the surface state of the substrate is constant. (Item 8) The determination method according to any one of items 1 to 6, characterized in that, in the specified step, based on the configuration information, measurement points located on lines extending radially from the center of gravity of the substrate are identified as two or more measurement points where the surface state of the substrate is constant. (Item 9) The substrate includes a plurality of shot regions on which a pattern is formed, The determination method according to any one of items 1 to 8, characterized in that the plurality of measurement points are set on the substrate such that each of the plurality of shot regions includes at least one measurement point. (Item 10) The determination method according to item 9, characterized in that the position of at least one measurement point on one shot area is the same in the plurality of shot areas. (Item 11) A lithography method for forming a pattern on a substrate, A step of measuring the surface height of the substrate by the first measuring unit, The process includes: positioning the substrate based on a value obtained by applying a correction value to the measurement result of the first measuring unit, The lithography method is characterized in that the correction value is determined using a second measurement unit according to the determination method described in any one of items 1 to 10. (Item 12) A forming step of forming a pattern on a substrate using the lithography method described in item 11, A processing step for processing the substrate that has undergone the forming step, A manufacturing process for producing an article from the substrate that has undergone the processing step, A method for manufacturing articles, characterized by including the following: (Item 13) A positioning device for positioning a substrate, A first measuring unit for measuring the surface height of the substrate, A second measuring unit for measuring the surface height of the substrate, The system includes a control unit that controls the positioning of the substrate based on a value obtained by applying a correction value to the measurement result of the first measurement unit, The control unit, From among a plurality of measurement points on the substrate whose surface height is measured by the first measurement unit, two or more measurement points where the surface state of the substrate is constant are identified based on configuration information indicating the configuration of the substrate. The surface height of a representative measurement point among the two or more measurement points is measured by the first measurement unit and the second measurement unit. Based on the measurement results of the first and second measurement units for the aforementioned representative measurement point, the correction value to be used in common for the two or more measurement points is determined. A positioning device characterized by the following features. (Item 14) A lithography apparatus for forming patterns on a substrate, A lithography apparatus characterized by having a positioning device as described in item 13.

[0057] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0058] 1: Substrate, 21: Optical measuring instrument (first measurement unit), 22: Air sensor (second measurement unit), 41: Substrate stage, CNT: Control unit, 100: Exposure device (lithography device)

Claims

1. A determination method for determining a correction value to be applied to the measurement result of a first measurement unit that measures the surface height of a substrate, using a second measurement unit that measures the surface height of the substrate, A selection step in which, from among a plurality of measurement points on the substrate whose surface height is measured by the first measurement unit, two or more measurement points are identified in which the surface state of the substrate is constant, based on configuration information indicating the configuration of the substrate, A measurement step comprising measuring the surface height of a representative measurement point among the two or more measurement points using the first measurement unit and the second measurement unit, A determination step in which, based on the measurement results of the first measurement unit and the second measurement unit for the aforementioned representative measurement point, the correction value to be used in common at the two or more measurement points is determined, A determination method characterized by including the following.

2. The determination method according to claim 1, characterized in that the first measurement unit and the second measurement unit measure the surface height of the substrate in different ways.

3. The first measurement unit measures the surface height of the substrate using light, The determination method according to claim 1, characterized in that the second measurement unit measures the surface height of the substrate using a gas.

4. The determination method according to claim 3, characterized in that the second measuring unit measures the height of the substrate based on the pressure in the pipeline while discharging gas through the pipeline.

5. The determination method according to claim 1, characterized in that the determination step involves determining the correction value based on the difference between the measurement result of the first measurement unit and the measurement result of the second measurement unit for the representative measurement point.

6. The determination method according to claim 1, characterized in that the configuration information includes at least one of the following: information indicating the process conditions of the substrate, information indicating the layout of the pattern formed on the substrate, and information indicating the arrangement of steps on the substrate.

7. The determination method according to claim 1, characterized in that, in the specified step, based on the configuration information, measurement points located on a circular line centered on the centroid of the substrate are identified as two or more measurement points where the surface state of the substrate is constant.

8. The determination method according to claim 1, characterized in that, in the specified step, based on the configuration information, measurement points located on lines extending radially from the center of gravity of the substrate are identified as two or more measurement points where the surface state of the substrate is constant.

9. The substrate includes a plurality of shot regions on which a pattern is formed, The determination method according to claim 1, characterized in that the plurality of measurement points are set on the substrate such that at least one measurement point is included in each of the plurality of shot regions.

10. The determination method according to claim 9, characterized in that the position of the at least one measurement point on one shot area is the same in the plurality of shot areas.

11. A lithography method for forming a pattern on a substrate, A step of measuring the surface height of the substrate by the first measuring unit, The process includes: positioning the substrate based on a value obtained by applying a correction value to the measurement result of the first measuring unit, A lithography method characterized in that the correction value is determined using a second measurement unit by the determination method described in any one of claims 1 to 10.

12. A forming step of forming a pattern on a substrate using the lithography method described in claim 11, A processing step for processing the substrate that has undergone the forming step, A manufacturing process for manufacturing an article from the substrate that has undergone the processing step, A method for manufacturing articles, characterized by including the following:

13. A positioning device for positioning a substrate, A first measuring unit for measuring the surface height of the substrate, A second measuring unit for measuring the surface height of the substrate, The system includes a control unit that controls the positioning of the substrate based on a value obtained by applying a correction value to the measurement result of the first measurement unit, The control unit, From among a plurality of measurement points on the substrate whose surface height is measured by the first measurement unit, two or more measurement points where the surface state of the substrate is constant are identified based on configuration information indicating the configuration of the substrate. The surface height of a representative measurement point among the two or more measurement points is measured by the first measurement unit and the second measurement unit. Based on the measurement results of the first and second measurement units for the aforementioned representative measurement point, the correction value to be used in common for the two or more measurement points is determined. A positioning device characterized by the following features.

14. A lithography apparatus for forming patterns on a substrate, A lithography apparatus characterized by having the positioning device described in claim 13.

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