Positioning method, substrate processing method, article manufacturing method, positioning device, and substrate processing device

Abstract

To provide a technique advantageous for accurately positioning a substrate using a phase pattern.SOLUTION: A positioning method for positioning a substrate having a phase pattern in which a plurality of lines are periodically arrayed and a first mark having lower measuring accuracy of a position than that of the phase pattern, using an imaging part having a visual field with a dimension smaller than the whole phase pattern includes: a measurement step of measuring the position of the first mark; an adjustment step of adjusting a relative position between the imaging part and the substrate so that the visual field is arranged in a target part of the phase pattern, on the basis of a measurement result of the measurement step; and a positioning step of positioning the substrate, on the basis of an image acquired by the imaging part at the relative position adjusted by the adjustment step.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a positioning method, a substrate processing method, an article manufacturing method, a positioning device, and a substrate processing device. [Background technology]

[0002] In order to form a pattern on a substrate with high accuracy in a lithography apparatus for manufacturing semiconductor devices, etc., it is important to position the substrate with high accuracy. Patent Documents 1 and 2 propose methods for positioning the substrate based on the results of measuring the positions of marks on the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2661015 [Patent Document 2] Patent No. 6719729 Summary of the Invention [Problem to be solved by the invention]

[0004] One method for positioning the substrate with high accuracy is to image a part of a phase pattern consisting of a periodic arrangement of a plurality of lines with an imaging unit having a field of view smaller than the entire phase pattern, and to position the substrate based on the image obtained by the imaging unit. In such a method, if there is a deviation in the relative position between the target part of the phase pattern whose image is to be acquired and the field of view of the imaging unit, it may be difficult to position the substrate with high accuracy.

[0005] Therefore, an object of the present invention is to provide an advantageous technique for accurately positioning a substrate using a phase pattern. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a positioning method as one aspect of the present invention is a positioning method for positioning a substrate having a phase pattern consisting of a periodic arrangement of a plurality of lines and a first mark having a lower position measurement accuracy than the phase pattern, using an imaging unit having a field of view smaller than the entire phase pattern, and is characterized in including a measurement step for measuring the position of the first mark, an adjustment step for adjusting the relative position of the imaging unit and the substrate based on the measurement result of the measurement step so that the field of view is positioned at a target portion of the phase pattern, and a positioning step for positioning the substrate based on an image acquired by the imaging unit at the relative position adjusted in the adjustment step.

[0007] Further objects and other aspects of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Effect of the Invention

[0008] According to the present invention, for example, it is possible to provide an advantageous technique for performing accurate positioning of a substrate using a phase pattern. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of an exposure apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing an example of an arrangement of a plurality of shot areas on a wafer; [Diagram 3] FIG. 1 is a schematic diagram showing an example of the configuration of an image capturing unit according to an embodiment of the present invention; [Figure 4] FIG. 1 is a diagram showing an example of the arrangement of marks and the like in a shot area; [Diagram 5] FIG. 1 shows an example of the configuration of a pre-alignment mark; [Figure 6] A diagram showing an example of the configuration of a fine alignment mark. [Figure 7] FIG. 1 is a diagram for explaining a plurality of lines constituting a phase pattern and the pitch (period) of the plurality of lines; [Figure 8]FIG. 1 shows an example of a phase pattern configuration. [Figure 9] 1 is a flowchart showing wafer processing according to a first embodiment; [Figure 10] 1 is a flowchart showing wafer processing according to a second embodiment. [Figure 11] 11 is a flow chart showing wafer processing according to a third embodiment. [Figure 12] 11 is a flow chart showing wafer processing according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] The positioning device according to the present invention is a device for positioning a substrate. Substrate processing apparatuses to which the positioning device is applied include lithography devices for forming a pattern on a substrate, processing devices for processing a substrate, and inspection devices for inspecting a substrate, but may also be other devices such as a microscope as long as they process a substrate. Lithography devices include exposure devices for exposing a substrate to transfer a pattern of an original onto the substrate, molding devices (imprint devices, flattening devices) for molding a composition on a substrate using an original (mold), and drawing devices for forming a pattern on a substrate by a charged particle beam. In the lithography device, for example, the positioning device according to the present invention can be used for aligning an original and a substrate. In the following, an example will be described in which an exposure device is used as the substrate processing apparatus and a wafer is used as the substrate.

[0012] First Embodiment A first embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing an example of the configuration of an exposure apparatus 10 of this embodiment. The exposure apparatus 10 of this embodiment may include an illumination optical system 1, a reticle stage 3 capable of holding and moving a reticle 2 (original), a projection optical system 4, a wafer stage 6 capable of holding and moving a wafer 5 (substrate), and a controller 8. The exposure apparatus 10 may be configured as a scanning exposure apparatus (scanner) that transfers a pattern of the reticle 2 onto the wafer 5 by driving the reticle 2 and the wafer 5 in synchronization with each other in the scanning direction. Alternatively, the exposure apparatus 10 may be configured as an exposure apparatus (stepper) that transfers a pattern of the reticle 2 onto the wafer 5 while the reticle 2 and the wafer 5 are stopped.

[0013] In this embodiment, the direction is indicated using an XYZ coordinate system in which the direction coinciding with the optical axis of the projection optical system 4 is the Z-axis direction, and the directions perpendicular to each other in a plane perpendicular to the Z-axis direction are the X-axis direction and the Y-axis direction. In the following, the direction parallel to the X-axis that defines the XYZ coordinate system is the X-axis direction, the direction parallel to the Y-axis that defines the XYZ coordinate system is the Y-axis direction, and the direction parallel to the Z-axis that defines the XYZ coordinate system is the Z-axis direction. In addition, the directions of rotation about the X-axis, Y-axis, and Z-axis are respectively the θX, θY, and θZ directions. When the exposure apparatus 10 is configured as a scanning exposure apparatus, the scanning direction of the reticle 2 and the wafer 5 is the Y-axis direction.

[0014] The illumination optical system 1 illuminates the reticle 2 held by the reticle stage 3 using exposure light emitted from a light source (not shown). The reticle stage 3 may be configured to be movable in directions perpendicular to the optical axis of the projection optical system 4 (XY directions) while holding the reticle 2. The projection optical system 4 projects the pattern of the reticle 2 onto the wafer 5 at a predetermined projection magnification β. In this embodiment, the projection optical system 4 may be configured as a reduced projection system with a projection magnification β of less than 1. The wafer stage 6 is configured to be movable in directions perpendicular to the optical axis of the projection optical system 4 (XY directions) while holding the wafer 5. In this embodiment, the wafer stage 6 may include a wafer chuck 6a that holds the wafer 5, and a drive mechanism 6b that drives the wafer chuck 6a (wafer 5) in the XY directions.

[0015] The control unit 8 is configured by a computer (information processing device) having a processor such as a CPU (Central Processing Unit) and a storage unit such as a memory, and controls each unit of the exposure apparatus 10 to control the exposure process of the wafer 5. The exposure process is a process of transferring the pattern of the reticle 2 onto the wafer 5, and may be understood as including alignment of the reticle 2 and the wafer 5. The exposure process may be performed sequentially for each of a plurality of shot areas 9 arranged on the wafer 5 as shown in FIG. 2. The control unit 8 may also be configured by a PLD (abbreviation of Programmable Logic Device) such as an FPGA (abbreviation of Field Programmable Gate Array), an ASIC (abbreviation of Application Specific Integrated Circuit), a general-purpose or dedicated computer with a program built in, or a combination of all or part of these.

[0016] The exposure apparatus 10 also includes an imaging unit 7 that images marks and the like provided on the wafer 5. The imaging unit 7 is configured to image the phase pattern 13, the fine alignment mark 12 (first mark), and the pre-alignment mark 11 (second mark) provided on the wafer 5. In the following, the phase pattern 13, the fine alignment mark 12, and the pre-alignment mark 11 may be collectively referred to as "marks and the like", and the details of the marks and the like will be described later. Here, the imaging unit 7 of this embodiment is disposed on the side of the projection optical system 4 and configured as an off-axis scope that images (detects) marks and the like on the wafer 5 without passing through the projection optical system 4, but is not limited thereto. For example, the imaging unit 7 may be configured as a TTL (Through The Lens) scope that images marks and the like on the wafer 5 via the projection optical system 4. The wafer stage 6, the imaging unit 7, and the control unit 8 may also be understood as configuring a positioning device that positions the wafer 5.

[0017] FIG. 3 is a schematic diagram showing a configuration example of the imaging unit 7. The imaging unit 7 may include a light source 71, a beam splitter 72, lenses 73-74, and a sensor 75. The sensor 75 may include a photoelectric conversion element such as a CCD or a CMOS. Illumination light from the light source 71 is reflected by the beam splitter 72 and passes through the lens 73 to illuminate the marks and the like on the wafer 5. Diffracted light from the marks and the like on the wafer 5 passes through the lens 73, the beam splitter 72, and the lens 74, and is received by the sensor 75. Each of the pre-alignment mark 11 and the fine alignment mark 12 is magnified to a predetermined magnification by the lenses 73-74 and imaged on the sensor 75. Here, in the case of this embodiment, the positioning of the wafer 5 is performed by a method that combines pre-alignment measurement that can search a wide range with low accuracy and fine alignment measurement that has a narrow search range with high accuracy. Therefore, it is preferable that the pre-alignment mark 11 and the fine alignment mark 12 have shapes suitable for this method.

[0018] Incidentally, in the exposure apparatus 10, in order to form a pattern on the wafer 5 with high accuracy, it is important to perform positioning of the wafer 5 with high accuracy. Conventionally, the wafer 5 has been positioned using only the pre-alignment mark 11 and the fine alignment mark 12. However, these marks 11-12 are generally arranged in the scribe region 9b (peripheral region) of each shot region 9 as shown in FIG. 4. Therefore, the position and distortion of the pattern formation region 9a where the device pattern is formed cannot be obtained with high accuracy only by using the marks 11-12, and it has been difficult to perform positioning of the wafer 5 with high accuracy. Each shot region 9 of the wafer 5 may include the pattern formation region 9a and the scribe region 9b. The scribe region 9b is a peripheral region surrounding the pattern formation region 9a, and may be understood as a region for separating (cutting) each shot region 9 (pattern formation region 9a) of the wafer 5.

[0019] As one method for positioning the wafer 5 with high accuracy, a part of the phase pattern 13 is imaged by the imaging unit 7 having a field of view smaller than the entire phase pattern 13, and the wafer 5 is positioned based on the image obtained by the imaging unit 7. The phase pattern 13 is a pattern in which a plurality of lines are periodically arranged in the vertical or horizontal direction, and is formed in the pattern-forming region 9a as shown in FIG. 4. The phase pattern 13 may be understood as a base pattern already formed in the pattern-forming region 9, and a plurality of phase patterns 13 are arranged in the pattern-forming region 9a. In the example of FIG. 4, only the phase pattern 13 arranged in a portion of the pattern-forming region 9 is illustrated for ease of understanding. However, the phase pattern 13 may be arranged in a plurality of places throughout the pattern-forming region 9a so that the shape (distortion) of the pattern-forming region 9 can be measured. For example, the phase pattern 13 may be arranged at the four corners of the pattern-forming region 9a, or may be arranged near the outer periphery of the pattern-forming region 9a (the boundary between the pattern-forming region 9a and the scribe region 9b).

[0020] There are several methods for measuring the position of such a phase pattern 13. For example, there is a template matching method that calculates the amount of phase shift using a template based on periodic pattern information, and a phase-only correlation method that extracts phase information for each pattern spatial frequency and measures the position. However, in the phase pattern 13, the width and pitch of the multiple lines constituting the phase pattern 13 are becoming narrower along with the recent miniaturization of device patterns. Therefore, a deviation may occur in the relative position between the target part of the phase pattern 13 from which an image should be acquired and the field of view of the imaging unit 7, and in this case, it may be difficult to perform the positioning of the wafer 5 with high accuracy.

[0021] Specifically, the target portion of the phase pattern 13 is set in advance to include at least two lines that should be included in the field of view of the imaging unit 7 among the multiple lines in the phase pattern 13. The image obtained by imaging a part of the phase pattern 13 by the imaging unit 7 includes only some of the multiple lines that constitute the phase pattern 13. Therefore, it is unclear which part of the phase pattern 13 is imaged in the image obtained by the imaging unit 7. In other words, even if the relative position between the target portion of the phase pattern 13 and the field of view of the imaging unit 7 is shifted and a line different from the line of the target portion of the phase pattern 13 is included in the image, the shift in the relative position cannot be grasped from the image. In this case, an error occurs in the position of the phase pattern 13 measured from the image, and it may be difficult to position the wafer 5 with high accuracy.

[0022] Therefore, in this embodiment, the position of the fine alignment mark 12 (first mark) is measured, and based on the measurement result, the relative position between the imaging unit 7 and the wafer 5 is adjusted so that the field of view of the imaging unit 7 is positioned at the target portion of the phase pattern 13. Then, based on an image of a portion of the phase pattern 13 acquired by the imaging unit 7 at the relative position between the imaging unit 7 and the wafer 5 after adjustment, the wafer 5 is positioned. This allows the field of view of the imaging unit 7 to be positioned accurately at the target portion of the phase pattern 13, so that the wafer 5 can be positioned with high accuracy.

[0023] Next, configuration examples of the pre-alignment mark 11, the fine alignment mark 12, and the phase pattern 13 will be described.

[0024] Fig. 5 shows an example of the configuration of the pre-alignment mark 11. The pre-alignment mark 11 is configured so that the measurement accuracy of its position is lower than that of the fine alignment mark 12, but has a wider search range than the fine alignment mark 12. Note that the pre-alignment mark 11 shown in Fig. 5 is merely an example, and any mark configured so that the position of the fine alignment mark 12 can be specified may be used.

[0025] FIG. 6 shows an example of the configuration of the fine alignment mark 12. The fine alignment mark 12 has a lower measurement accuracy of its position than that of the phase pattern 13. The fine alignment mark 12 shown in FIG. 6 is merely an example, and may be any mark configured to specify the position of the target area of ​​the phase pattern 13. The fine alignment mark 12 may be configured so that the measurement error of the position of the fine alignment mark 12 is equal to or less than the pitch of the lines in the phase pattern 13 (equal to or less than the period λ of the lines). For example, the fine alignment mark 12 may be configured so that the measurement error of the position of the fine alignment mark 12 is equal to or less than ¼ of the pitch of the lines in the phase pattern 13 (equal to or less than λ / 4). In this case, the position of the phase pattern 13 can be specified with an accuracy of λ / 4 based on the measurement result of the position of the fine alignment mark 12. FIG. 7 is a diagram for explaining the lines constituting the phase pattern 13 and the pitch (period) of the lines.

[0026] FIG. 8 shows an example of the configuration of the phase pattern 13. FIG. 8(a) shows a phase pattern 13a formed by arranging a plurality of lines extending in the X direction. The phase pattern 13a shown in FIG. 8(a) is used to measure the position of the wafer 5 in the Y direction. FIG. 8(b) shows a phase pattern 13b formed by arranging a plurality of lines extending in the Y direction. The phase pattern 13b shown in FIG. 8(b) is used to measure the position of the wafer 5 in the X direction. Each of the phase patterns 13a to 13b can be disposed at a plurality of locations (for example, at least the four corners of the pattern formation region 9a) throughout the entire pattern formation region 9a of each shot region 9.

[0027] In the phase pattern 13, the pattern period (i.e., the pitch of the multiple lines constituting the phase pattern 13) has become smaller with the recent miniaturization of device patterns. The phase pattern 13 is configured to be able to measure the position with a higher measurement accuracy than the measurement accuracy of the position of the fine alignment mark 12. In addition, as shown in Figs. 8(a) to (b), the phase pattern 13 has a dimension larger than the field of view 7a of the imaging unit 7. In other words, the imaging unit 7 has a field of view 7a with a dimension smaller than the entire phase pattern 13, and is configured to image only a part of the phase pattern 13 by the field of view 7a. Therefore, as described above, it is unclear which part of the phase pattern 13 is imaged in the image obtained by the imaging unit 7, and in order to perform positioning of the wafer 5 with high accuracy, the relative position between the target part of the phase pattern 13 and the field of view 7a of the imaging unit 7 is important.

[0028] The positioning of the wafer 5 in this embodiment will be described below. Fig. 9 is a flowchart showing wafer processing including the positioning of the wafer 5. The flowchart in Fig. 9 can be executed by the control unit 8. Here, the flowchart in Fig. 9 shows an example focusing on a target shot area that is to be subjected to exposure processing among a plurality of shot areas 9 on the wafer 5. When performing exposure processing on each of the plurality of shot areas 9 on the wafer 5, the flowchart in Fig. 9 can be executed repeatedly.

[0029] In step S101, the control unit 8 loads the wafer 5 onto the wafer stage 6 using a wafer transport mechanism (not shown). Next, in step S102, the control unit 8 performs pre-alignment measurement to measure the position of the pre-alignment mark 11 using the imaging unit 7. For example, the control unit 8 moves the wafer 5 using the wafer stage 6 so that the pre-alignment mark 11 of the wafer 5 falls within the field of view 7a of the imaging unit 7, and causes the imaging unit 7 to capture an image of the pre-alignment mark 11. This allows the control unit 8 to measure the position of the pre-alignment mark 11 based on the image of the pre-alignment mark 11 obtained by the imaging unit 7.

[0030] Here, in this embodiment, an example in which the pre-alignment measurement is performed using the imaging unit 7 will be described, but the present invention is not limited thereto, and the pre-alignment measurement may be performed using a scope (imaging unit, detection unit) different from the imaging unit 7. Furthermore, the pre-alignment measurement is not limited to a state in which the wafer 5 is held by the wafer stage 6, and may be performed before the wafer 5 is loaded onto the wafer stage 6. For example, the pre-alignment measurement may be performed using a scope different from the imaging unit 7 in a state in which the wafer 5 is held by a stage (pre-alignment stage) different from the wafer stage 6. In this case, the wafer 5 may be loaded onto the wafer stage 6 (step S101) after the pre-alignment measurement is performed. Furthermore, if the position of the fine alignment mark 12 can be specified without performing the pre-alignment measurement, the pre-alignment measurement (step S102) may be omitted.

[0031] In step S103, the control unit 8 specifies the position of the fine alignment mark 12 based on the measurement result of the pre-alignment measurement. Next, in step S104, the control unit 8 performs fine alignment measurement to measure the position of the fine alignment mark 12 by the imaging unit 7. For example, the control unit 8 moves the wafer 5 by the wafer stage 6 so that the fine alignment mark 12 of the wafer 5 falls within the field of view 7a of the imaging unit 7 based on the position of the fine alignment mark 12 specified in step S103. Then, the control unit 8 causes the imaging unit 7 to capture an image of the fine alignment mark 12. This allows the control unit 8 to measure the position of the fine alignment mark 12 based on the image of the fine alignment mark 12 obtained by the imaging unit 7.

[0032] In step S105, based on the measurement result of the fine alignment measurement in step S104, the control unit 8 adjusts the relative position between the wafer 5 and the imaging unit 7 to image the target portion of the phase pattern 13. For example, based on the position of the fine alignment mark 12 measured by the fine alignment measurement, the control unit 8 adjusts the relative position between the wafer 5 and the imaging unit 7 by the wafer stage 6 so that the field of view 7a of the imaging unit 7 is positioned at the target portion of the phase pattern 13.

[0033] In step S106, the control unit 8 captures an image of a part of the phase pattern 13 by the imaging unit 7 at the relative position adjusted in step S105. Next, in step S107, the positioning of the wafer 5 is performed. For example, the control unit 8 identifies the position of the phase pattern 13 based on the phase in the image acquired by the imaging unit 7 in step S106, and positions the wafer 5 based on the identified position of the phase pattern 13. The phase in the image may be understood as the position in the image of at least two lines that are set in advance to be included in the target portion among the multiple lines in the phase pattern 13. Here, when the position of each of the multiple phase patterns 13 arranged inside the shot area 9 (pattern formation area 9a) is measured, in addition to the position of the shot area 9, the shape of the shot area 9 can also be obtained. That is, the positioning of the wafer 5 may include determining the shape of the target shot area (pattern formation area 9a) in addition to determining the position of the target shot area (pattern formation area 9a).

[0034] In step S108, the control unit 8 performs an exposure process on the wafer 5 positioned in step S107. As described above, the exposure process is a process of transferring the pattern of the reticle 2 onto the wafer 5, and includes alignment between the reticle 2 and the wafer 5. The alignment may include controlling the relative position between the reticle 2 and the wafer 5 based on the position of the target shot area determined in step S107. The alignment may also include correcting the pattern image of the reticle 2 so that the overlay error between the base pattern of the wafer 5 and the pattern image of the reticle 2 falls within an allowable range based on the shape of the target shot area determined in step S107. Next, in step S109, the control unit 8 causes the wafer 5 to be carried out from the wafer stage 6 by a wafer transport mechanism (not shown).

[0035] As described above, in this embodiment, the relative position between the imaging unit 7 and the wafer 5 is adjusted based on the measurement result of the position of the fine alignment mark 12 so that the field of view 7a of the imaging unit 7 is located at the target portion of the phase pattern 13. Then, the wafer 5 is positioned based on an image of a portion of the phase pattern 13 acquired by the imaging unit 7 at the relative position between the imaging unit 7 and the wafer 5 after the adjustment. This allows the field of view 7a of the imaging unit 7 to be accurately located at the target portion of the phase pattern 13, so that the wafer 5 can be positioned with high accuracy.

[0036] <Second embodiment> A second embodiment of the present invention will be described. In the second embodiment, in order to shorten the time required for alignment measurement and improve the throughput of the exposure apparatus 10, the positioning of other shot areas can be performed based on the measurement results of a predetermined shot area among the multiple shot areas 9 on the wafer 5. The predetermined shot area may be the shot area that is to be subjected to the exposure process first among the multiple shot areas 9 on the wafer 5. This embodiment basically follows on from the first embodiment, and can follow the first embodiment except for the matters mentioned below.

[0037] Fig. 10 is a flowchart showing wafer processing in this embodiment. The flowchart in Fig. 10 can be executed by the control unit 8. In this embodiment, at least one of the position and shape measured using the phase pattern 13 for a predetermined shot area is stored (S209). Then, for the subsequent shot areas, the position of the phase pattern 13 is not measured, and the wafer 5 is positioned using at least one of the position and shape of the predetermined shot area.

[0038] Steps S201 to S204 are the same as steps S101 to S104 in the flowchart of Fig. 9 described in the first embodiment, and therefore will not be described here. In step S205, the control unit 8 determines whether the target shot area to be subjected to the exposure process is a predetermined shot area. If the target shot area is a predetermined shot area, the process proceeds to step S206, and if the target shot area is not a predetermined shot area, the process proceeds to step S210.

[0039] Steps S206 to S208 are similar to steps S105 to S107 in the flowchart of FIG. 9 described in the first embodiment, and therefore description thereof will be omitted here. In step S209, the control unit 8 stores the position and shape of the predetermined shot area measured in step S208. Note that, in this embodiment, an example is shown in which both the position and the shape of the predetermined shot area are stored in step S209, but this is not limiting, and at least one of the position and the shape of the predetermined shot area may be stored. For example, only the shape of the predetermined shot area may be stored.

[0040] In step S210, the control unit 8 performs positioning of the wafer 5 for another shot area different from the predetermined shot area based on the position and shape measured for the predetermined shot area. For example, the control unit 8 may perform positioning of the wafer 5 by applying the position and shape measured for the predetermined shot area as is to the other shot area.

[0041] In step S211, the control unit 8 performs exposure processing on the target shot area. This step S211 is similar to step S108 in the flowchart of FIG. 9 described in the first embodiment, and therefore description thereof will be omitted here. Next, in step S212, the control unit 8 determines whether exposure processing has been performed on all of the multiple shot areas 9 on the wafer 5. If there is a shot area on which exposure processing has not been performed, the process proceeds to step S205. On the other hand, if exposure processing has been performed on all shot areas, the process proceeds to step S213, where the control unit 8 transports the wafer 5 out from the wafer stage 6 by a wafer transport mechanism (not shown).

[0042] As described above, in this embodiment, based on the position and shape measured for the predetermined shot area, positioning is performed for other shot areas different from the predetermined shot area. This can omit the measurement of the position of the phase pattern for the other shot area, which can be advantageous in terms of the throughput of the exposure apparatus 10. Here, in this embodiment, an example in which there is one predetermined shot area has been described, but there may be multiple predetermined shot areas. In this case, the control unit 8 performs global alignment using the positions and shapes measured for each of the multiple predetermined shot areas, and can position the wafer 5 based on the positions and shapes of the other shot areas obtained thereby.

[0043] <Third embodiment> A third embodiment of the present invention will be described. Even if the relative position between the wafer 5 and the imaging unit 7 is adjusted based on the measurement result of the fine alignment measurement, an error (i.e., pitch deviation) may occur in the relative position. Therefore, in the third embodiment, the relative position between the wafer 5 and the imaging unit 7 adjusted based on the measurement result of the fine alignment measurement is evaluated. The evaluation of the relative position can be performed by performing the fine alignment measurement again. Note that this embodiment basically inherits the first embodiment, and can follow the first embodiment except for the matters mentioned below. Also, the second embodiment may be applied to this embodiment.

[0044] Fig. 11 is a flowchart showing wafer processing according to this embodiment. The flowchart in Fig. 11 can be executed by the control unit 8. Here, steps S301 to S306 in the flowchart in Fig. 11 are similar to steps S101 to S106 in the flowchart in Fig. 9 described in the first embodiment, and therefore description thereof will be omitted here.

[0045] Steps S307 to S310 are evaluation steps for evaluating the relative position between wafer 5 and imaging unit 7 adjusted in step S305.

[0046] In step S307, control unit 8 determines (calculates) the position and shape of the target shot area based on the image acquired in step S306 by imaging unit 7. Next, in step S308, control unit 8 moves wafer 5 by wafer stage 6 to a position for performing fine alignment measurement based on the position and shape of the target shot area determined in step S307.

[0047] In step S309, the control unit 8 performs fine alignment measurement again, in which the image capture unit 7 measures the position of the fine alignment mark 12 at the position of the wafer 5 moved in step S308. Next, in step S310, the control unit 8 evaluates the relative position between the wafer 5 adjusted in step S305 and the image capture unit 7 based on the position of the fine alignment mark 12 measured in step S309. For example, the control unit calculates the difference between the position of the fine alignment mark 12 measured in step S309 and a specified position, and can evaluate the relative position between the wafer 5 adjusted in step S305 and the image capture unit 7 depending on whether the difference is within an allowable range. Here, the specified position may be a reference point (center of field of view) within the field of view 7a of the image capture unit 7, or may be the position of the fine alignment mark 12 measured in step S304.

[0048] In step S311, the control unit 8 judges whether or not to perform positioning of the wafer 5 (i.e., exposure processing) based on the evaluation result of step S310. For example, if the difference between the position of the fine alignment mark 12 measured in step S309 and the specified position is within the allowable range, the control unit 8 judges to perform positioning of the wafer 5 (exposure processing) and proceeds to step S312. In this case, the control unit 8 adjusts the relative position of the wafer 5 and the imaging unit 7 as in step S305, and performs positioning of the wafer 5 based on the phase in the image acquired by the imaging unit 7 at that relative position. On the other hand, if the difference is outside the allowable range, the control unit 8 judges not to perform positioning of the wafer 5 (exposure processing) and proceeds to step S313 to stop the process flow (error stop). Note that in step S313, an error notification that a measurement error has occurred may be performed.

[0049] In step S314, the control unit 8 performs exposure processing on the wafer 5 positioned in step S312. This step S314 is similar to step S108 in the flowchart of Fig. 9 described in the first embodiment, and therefore a description thereof will be omitted here. Next, in step S315, the control unit 8 causes a wafer transport mechanism (not shown) to unload the wafer 5 from the wafer stage 6.

[0050] As described above, in this embodiment, the relative position between the wafer 5 adjusted based on the measurement result of the fine alignment measurement and the imaging unit 7 is evaluated, and based on the evaluation result, it is determined whether or not to perform positioning of the wafer 5 (i.e., exposure processing). This makes it possible to prevent the occurrence of product defects due to erroneous measurement of the phase pattern, etc.

[0051] <Fourth embodiment> A fourth embodiment of the present invention will be described. In this embodiment, an example will be described in which, when it is known in advance that the shape of each shot area 9 of the wafer 5 is distorted, the relative position between the wafer 5 and the imaging unit 7 for imaging a part of the phase pattern 13 is adjusted in consideration of the distortion. Note that this embodiment basically inherits the first embodiment, and can follow the first embodiment except for the matters mentioned below. In addition, at least one of the second embodiment and the third embodiment may be applied to this embodiment.

[0052] 12 is a flowchart showing the wafer processing of this embodiment. The flowchart in FIG.

[0053] In step S401, controller 8 loads wafer 5 onto wafer stage 6 using a wafer transport mechanism (not shown). Next, in step S402, controller 8 acquires shape information indicating the shape of the target shot area. The shape information can be, for example, information indicating the shape of the target shot area acquired by a measurement device disposed outside exposure apparatus 10. The shape information may be understood as information indicating the positional relationship between fine alignment mark 12 and phase pattern 13. Note that step S402 may be executed before step S401.

[0054] Steps S403 to S405 are the same as steps S102 to S104 in the flowchart of FIG. 9 described in the first embodiment, so that the description here is omitted. Next, in step S406, the control unit 8 adjusts the relative position between the wafer 5 and the imaging unit 7 to image the target portion of the phase pattern 13 based on the measurement result of the fine alignment measurement in step S405 and the shape information acquired in step S402. For example, the measurement result of the fine alignment measurement in step S405 includes the position of the fine alignment mark 12, and the shape information acquired in step S402 includes the positional relationship between the fine alignment mark 12 and the phase pattern 13. In addition, since the target portion of the phase pattern 13 is set in advance, the position of the target portion in the entire phase pattern 13 is known. Therefore, the control unit 8 can specify the position of the target portion of the phase pattern 13 based on these pieces of information, and adjust the relative position between the wafer 5 and the imaging unit 7 by the wafer stage 6 so that the field of view 7a of the imaging unit 7 is located at the target portion of the phase pattern 13.

[0055] Steps S407 to S410 are similar to steps S106 to S109 in the flowchart of FIG. 9 described in the first embodiment, and therefore a description thereof will be omitted here.

[0056] As described above, in this embodiment, the relative position between the wafer 5 and the imaging unit 7 for imaging the target portion of the phase pattern 13 is adjusted based on information (shape information) indicating the positional relationship between the fine alignment mark 12 and the phase pattern 13. As a result, even if distortion occurs in the target shot area, the relative position between the wafer 5 and the imaging unit 7 can be accurately adjusted based on the measurement result of the fine alignment measurement so that the field of view 7a of the imaging unit 7 is positioned in the target area of ​​the phase pattern 13.

[0057] <Embodiment of the article manufacturing method> The above-mentioned substrate processing apparatus can be used to implement an article manufacturing method for manufacturing various articles (semiconductor IC elements, liquid crystal display elements, MEMS, etc.). The article manufacturing method in the embodiment of the present invention is suitable for manufacturing articles such as devices (semiconductor elements, magnetic storage media, liquid crystal display elements, etc.). Such an article manufacturing method includes a processing step of processing a substrate by the above-mentioned substrate processing apparatus, and a manufacturing step of manufacturing an article from a member that has undergone the processing step. When a lithography apparatus is used as the substrate processing apparatus, the processing step may be understood as including a step of forming a pattern on the substrate. Furthermore, such an article manufacturing method may include other well-known steps (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method in the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to the conventional method.

[0058] <Summary of the embodiment> The disclosure of the present specification includes at least the following positioning method, substrate processing method, article manufacturing method, positioning apparatus, and substrate processing apparatus. (Item 1) A method for positioning a substrate having a phase pattern including a plurality of periodically arranged lines and a first mark having a lower position measurement accuracy than the phase pattern, by using an imaging unit having a field of view smaller than the entire phase pattern, comprising: a measuring step of measuring a position of the first mark; an adjustment step of adjusting a relative position between the imaging unit and the substrate based on a measurement result of the measurement step so that the field of view is positioned in a target portion of the phase pattern; a positioning step of positioning the substrate based on an image acquired by the imaging unit at the relative position adjusted in the adjustment step; A positioning method comprising: (Item 2) 2. The positioning method according to item 1, wherein in the positioning step, the substrate is positioned based on a position of the phase pattern identified from a phase in an image acquired by the imaging unit at the relative position adjusted in the adjustment step. (Item 3) 3. The positioning method according to item 1 or 2, characterized in that the target portion is set in advance as a portion of the phase pattern from which an image should be acquired by the imaging unit. (Item 4) The positioning method according to any one of items 1 to 3, characterized in that the target portion is set in advance to include at least two lines among the multiple lines in the phase pattern that should be within the field of view. (Item 5) 5. The positioning method according to any one of items 1 to 4, wherein the first mark is configured so that a measurement error in the position of the first mark is equal to or less than a pitch of the multiple lines. (Item 6) 6. The positioning method according to any one of items 1 to 5, characterized in that the first mark is configured so that a measurement error in the position of the first mark is ¼ or less of the pitch of the multiple lines. (Item 7) the substrate includes a pattern formation region in which a device pattern is formed and a peripheral region surrounding the pattern formation region; 7. The positioning method according to any one of items 1 to 6, characterized in that the phase pattern is arranged in the pattern formation region, and the first mark is arranged in the peripheral region. (Item 8) A plurality of the phase patterns are arranged in the pattern formation region, 8. The positioning method according to item 7, characterized in that in the positioning step, a shape of the pattern formation region is determined by measuring a position of each of the phase patterns arranged in the pattern formation region, and the substrate is positioned based on the shape of the pattern formation region. (Item 9) The method further includes, before the measuring step, a step of measuring a position of a second mark provided on the substrate and specifying a position of the first mark based on a measurement result, 9. The positioning method according to any one of items 1 to 8, wherein a measurement accuracy of the position of the second mark is lower than a measurement accuracy of the position of the first mark. (Item 10) the substrate includes a pattern formation region in which a device pattern is formed and a peripheral region surrounding the pattern formation region; 10. The positioning method according to item 9, wherein the phase pattern is arranged in the pattern forming area, and the first mark and the second mark are arranged in the peripheral area. (Item 11) an evaluation step of evaluating the relative position adjusted in the adjustment step; a determination step of determining whether or not to execute the positioning step based on an evaluation result of the evaluation step; 11. The positioning method according to any one of items 1 to 10, further comprising: (Item 12) The method further includes the step of acquiring information indicating a positional relationship between the first mark and the phase pattern, 12. The positioning method according to any one of items 1 to 11, wherein in the adjusting step, the relative position is adjusted further based on the information acquired in the acquiring step. (Item 13) A substrate processing method for processing a substrate, comprising the steps of: A step of positioning the substrate by using the positioning method according to any one of items 1 to 12; processing the positioned substrate; A substrate processing method comprising: (Item 14) Processing a substrate using the substrate processing method according to item 13; producing an article from the processed substrate; A method for manufacturing an article, comprising: (Item 15) 1. A positioning apparatus for positioning a substrate having a phase pattern including a plurality of lines periodically arranged thereon and a first mark having a position measurement accuracy lower than that of the phase pattern, comprising: a stage for holding and moving the substrate; An imaging unit having a field of view smaller than the entire phase pattern; a control unit that controls the positioning of the substrate by driving the stage; Equipped with a control unit that adjusts a relative position between the imaging unit and the substrate based on a measurement result of the position of the first mark so that the field of view is positioned at a target portion of the phase pattern, and positions the substrate based on an image acquired by the imaging unit at the adjusted relative position. (Item 16) A substrate processing apparatus for processing a substrate, Item 16 includes the positioning device according to item 15, The substrate processing apparatus processes the substrate positioned by the positioning device.

[0059] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0060] 1: illumination optical system, 2: reticle (master), 3: reticle stage, 4: projection optical system, 5: wafer (substrate), 6: wafer stage, 7: imaging unit, 8: control unit, 10: exposure device

Claims

1. A positioning method for positioning a substrate having a phase pattern including a plurality of periodically arranged lines and a first mark having a lower position measurement accuracy than the phase pattern, by using an imaging unit having a field of view smaller than the entire phase pattern, the method comprising: a measuring step of measuring a position of the first mark; an adjustment step of adjusting a relative position between the imaging unit and the substrate based on a measurement result of the measurement step so that the field of view is positioned in a target portion of the phase pattern; a positioning step of positioning the substrate based on an image acquired by the imaging unit at the relative position adjusted in the adjustment step; A positioning method comprising:

2. The positioning method according to claim 1, characterized in that, in the positioning step, the substrate is positioned based on the position of the phase pattern identified from a phase in an image acquired by the imaging unit at the relative position adjusted in the adjustment step.

3. The positioning method according to claim 1 , wherein the target portion is set in advance as a portion of the phase pattern from which an image should be acquired by the imaging unit.

4. The method according to claim 1 , wherein the target portion is preset to include at least two lines of the plurality of lines in the phase pattern that should be within the field of view.

5. 2. The positioning method according to claim 1, wherein the first mark is configured so that a measurement error in the position of the first mark is equal to or smaller than a pitch of the plurality of lines.

6. 2. The positioning method according to claim 1, wherein the first mark is configured so that a measurement error in the position of the first mark is equal to or smaller than 1 / 4 of a pitch of the plurality of lines.

7. the substrate includes a pattern formation region in which a device pattern is formed and a peripheral region surrounding the pattern formation region; 2. The method according to claim 1, wherein the phase pattern is arranged in the pattern forming region, and the first mark is arranged in the peripheral region.

8. A plurality of the phase patterns are arranged in the pattern formation region, 8. The positioning method according to claim 7, wherein in the positioning step, a shape of the pattern formation area is determined by measuring a position of each of the phase patterns arranged in the pattern formation area, and the substrate is positioned based on the shape of the pattern formation area.

9. a step of measuring a position of a second mark provided on the substrate and specifying a position of the first mark based on a measurement result, the step being performed before the measurement step; 2. The positioning method according to claim 1, wherein the measurement accuracy of the position of the second mark is lower than the measurement accuracy of the position of the first mark.

10. the substrate includes a pattern formation region in which a device pattern is formed and a peripheral region surrounding the pattern formation region; 10. The positioning method according to claim 9, wherein the phase pattern is arranged in the pattern forming region, and the first mark and the second mark are arranged in the peripheral region.

11. an evaluation step of evaluating the relative position adjusted in the adjustment step; a determination step of determining whether or not to execute the positioning step based on an evaluation result of the evaluation step; The method of claim 1 further comprising:

12. The method further includes the step of acquiring information indicating a positional relationship between the first mark and the phase pattern, 2. The method according to claim 1, wherein in the adjusting step, the relative position is adjusted further based on the information acquired in the acquiring step.

13. A substrate processing method for processing a substrate, comprising the steps of: performing positioning of the substrate by using the positioning method according to any one of claims 1 to 12; processing the positioned substrate; A substrate processing method comprising:

14. Processing a substrate using the substrate processing method according to claim 13; producing an article from the processed substrate; A method for manufacturing an article, comprising:

15. 1. A positioning apparatus for positioning a substrate having a phase pattern including a plurality of lines periodically arranged thereon and a first mark having a position measurement accuracy lower than that of the phase pattern, comprising: a stage for holding and moving the substrate; An imaging unit having a field of view smaller than the entire phase pattern; a control unit that controls the positioning of the substrate by driving the stage; Equipped with The control unit adjusts the relative position between the imaging unit and the substrate based on the measurement results of the position of the first mark so that the field of view is positioned at the target portion of the phase pattern, and positions the substrate based on an image acquired by the imaging unit at the adjusted relative position.

16. A substrate processing apparatus for processing a substrate, The positioning device according to claim 15, The substrate processing apparatus processes the substrate positioned by the positioning device.

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