Detection device, lithography apparatus, and article manufacturing method

Abstract

A detection device detects the relative position between a first and a second overlapping mark. The device includes an illumination system and a detection system. The illumination system is configured to illuminate the first and second marks with illumination light. The detection system is configured to form an image on the imaging surface of an image sensor using light diffracted from the first and second marks. The first and second marks are configured to form optical information on the imaging surface indicating the relative position in a first or second direction. The illumination light passes through the optical axis of the illumination system only on the pupil surface of the illumination system. A light-shielding body provided on the pupil surface of the detection system includes: a first light-shielding portion intersecting the optical axis of the detection system in a direction conjugate to the first direction, and a second light-shielding portion intersecting the optical axis of the detection system in a direction conjugate to the second direction.

Description

Technical Field

[0001] The present invention relates to a detection device, a lithography device and an article manufacturing method. Prior Art

[0002] An imprinting device brings a mold into contact with an imprint material placed on a substrate and cures the imprint material, thereby forming a pattern made of the cured imprint material. In this imprinting device, it is important to correctly align the substrate and mold. Japanese Patent Application Publication No. 2008-522412 describes a technique for aligning the substrate and mold using a mark formed by a diffraction grating provided on the substrate and a mark formed by a diffraction grating provided on the mold.

[0003] When a mark is illuminated, light reflected from the edge of the mark, which serves as the boundary between the mark and the area outside the mark, enters the image sensor as noise light, potentially reducing mark detection accuracy. In particular, as the mark's area decreases, the noise light's influence on the image formed by the light used to detect positional information from the mark increases, potentially significantly reducing detection accuracy. Summary of the Invention

[0004] The present invention provides a technique that facilitates detecting the relative position between a first mark and a second mark provided on a first object and a second object, respectively, with high detection accuracy.

[0005] One aspect of the present invention provides a detection device for detecting the relative position between a first mark and a second mark provided on a first object and a second object, respectively, arranged to overlap each other. The device includes: an illumination system configured to illuminate the first mark and the second mark with illumination light; and a detection system including an image sensor and configured to form an image on an imaging surface of the image sensor using light diffracted from the first mark and the second mark illuminated by the illumination system. The first mark and the second mark are configured to form optical information on the imaging surface indicating the relative position in a first direction or a second direction orthogonal to the first direction. The illumination light is light that passes only through the optical axis of the illumination system and light near the optical axis on a pupil surface of the illumination system. A light shield includes a first light shielding portion that intersects the optical axis of the detection system in a direction parallel to a third direction and a second light shielding portion that intersects the optical axis of the detection system in a direction parallel to a fourth direction. The light shield is provided on the pupil surface of the detection system. The third direction is conjugate to the first direction, and the fourth direction is conjugate to the second direction.

[0006] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Simple diagram description

[0007] [FIG. 1A] is a view illustrating the light intensity distribution of a pupil surface of an illumination system;

[0008] [FIG. 1B] is a view illustrating the light intensity distribution of the pupil surface of the detection system;

[0009] [FIG. 2] is a view illustrating a configuration of an imprint apparatus as an example of a lithography apparatus;

[0010] [Figure 3] is a view illustrating the configuration of the detection device;

[0011] [FIG. 4A] is a view of an example mold mark;

[0012] [FIG. 4B] is a view of an example substrate marking;

[0013] [FIGS. 5A] to [FIG. 5D] are views illustrating diffraction gratings that produce moiré fringe;

[0014] [FIG. 6A] and [FIG. 6B] are views illustrating diffraction gratings that produce moiré;

[0015] [Figure 7] is a view of an example pattern edge light;

[0016] [FIG. 8A] is a view illustrating an illumination aperture stop configured on a pupil surface of an illumination system;

[0017] [FIG. 8B] is a view illustrating an illumination aperture stop configured on the pupil surface of the detection system;

[0018] 9A and 9B are diagrams for explaining the influence of the presence or absence of pattern edge light on the moiré phase difference measurement; and

[0019] [FIG. 10A] to [FIG. 10F] are views illustrating a method of manufacturing an article. Implementation Method

[0020] Below, embodiments will be described in detail with reference to the accompanying drawings. Please note that the following embodiments are not intended to limit the scope of the claimed invention. While various features are described in the embodiments, this does not limit the invention to requiring all of these features, and multiple such features may be appropriately combined. Additionally, in the accompanying drawings, identical or similar components are given the same reference numerals, and duplicate descriptions thereof are omitted.

[0021] Figure 2 shows the configuration of an imprint apparatus 10, an example of a lithography apparatus for transferring a pattern from an original object to a substrate. The imprint apparatus 10 is used to manufacture devices such as semiconductor devices. It forms a pattern on substrate 17, a target object, by molding an uncured imprint material 18 using a mold 16 onto substrate 17, thereby forming a cured product of the imprint material 18. The patterning process for forming a pattern on substrate 17 using the imprint apparatus 10 may include a contact step, a filling and alignment step, a curing step, and a separation step. In the contact step, the imprint material 18 on the shot region of substrate 17 and the pattern region 16a of mold 16 are brought into contact with each other. In the filling and alignment step, the space defined by the shot region of substrate 17 and the pattern region 16a of mold 16 is filled with the imprint material 18, and the shot region of substrate 17 and the pattern region 16a of mold 16 are aligned. The shot region is the area where a pattern is formed during a single patterning process. In other words, the shot region is a region to which the pattern region 16 a of the mold 16 is transferred through one patterning process.

[0022] The imprint material is a curable composition (also called an uncured resin) that cures upon receiving curing energy. The curing energy can be electromagnetic waves or heat. The electromagnetic wave can be, for example, light within the wavelength range of 10 nm to 1 mm, such as infrared light, visible light, or ultraviolet light. The curable composition can be cured by light irradiation or heating. A photocurable composition that cures upon light irradiation contains at least a polymerizable compound and a photopolymerization initiator, and may, if desired, further contain a non-polymerizable compound or solvent. The non-polymerizable compound is at least one selected from a sensitizer, a hydrogen donor, an internal mold release agent, a surfactant, an antioxidant, and a polymer component. The imprint material can be applied to the substrate in the form of droplets or as islands or films formed by connecting multiple droplets. The imprint material can be supplied to the substrate in the form of a film using a spin coater or a slit coater. The viscosity of the imprint material (at 25°C) can be, for example, 1 to 100 mPa·s. Examples of materials for the substrate include glass, ceramics, metals, semiconductors (such as Si, GaN, and SiC), and resins. As needed, a member made of a different material from the substrate may be disposed on the surface of the substrate. The substrate is, for example, a silicon wafer, a compound semiconductor wafer, or silica glass. The following describes an example using a photocurable composition as the imprint material, but this is not intended to limit the type of imprint material.

[0023] In this specification and accompanying drawings, directions are expressed in an XYZ coordinate system, where the direction parallel to the surface of substrate 17 is defined as the XY plane. Directions parallel to the X, Y, and Z axes of the XYZ coordinate system are the X, Y, and Z directions, respectively. Rotation about the X, Y, and Z axes is denoted by θX, θY, and θZ, respectively. Control or actuation regarding the X, Y, and Z axes refers to control or actuation regarding directions parallel to the X, Y, and Z axes, respectively. Furthermore, control or actuation regarding the θX, θY, and θZ axes refers to control or actuation regarding rotation about an axis parallel to the X, Y, and Z axes, respectively. Furthermore, control or actuation regarding the θX, θY, and θZ axes refers to control or actuation regarding rotation about an axis parallel to the X, Y, and Z axes, respectively. Position refers to information that can be specified based on coordinates on the X, Y, and Z axes, while direction refers to information that can be specified using values ​​on the θX, θY, and θZ axes. Positioning means controlling position and / or orientation. Alignment (positioning) can include controlling the position and / or orientation of at least one of substrate 17 and the mold to reduce alignment errors (overlay errors) between the shot area of ​​substrate 17 and the pattern area of ​​mold 16. Furthermore, alignment can include controlling to correct or change the shape of at least one of the shot area of ​​substrate 17 and the pattern area of ​​mold 16. The contact and separation steps can be performed by driving mold 16 via mold drive mechanism 13, but can also be performed by driving substrate 17 via substrate drive mechanism 14. Alternatively, the contact and separation steps can be performed by driving mold 16 via mold drive mechanism 13 and substrate 17 via substrate drive mechanism 14.

[0024] The imprint apparatus 10 may include a curing unit 11, a detection device 12, a mold drive mechanism 13, a substrate drive mechanism 14, and a control unit C. The imprint apparatus 10 may also include an application unit 15. After a contact step in which the mold 16 is brought into contact with the imprint material 18 on the substrate 17, the curing unit 11 irradiates the imprint material 18 with light, such as ultraviolet light, as curing energy, thereby curing the imprint material 18. The curing unit 11 includes, for example, a light source and a plurality of optical elements for uniformly irradiating the pattern region 16a of the mold 16, serving as the irradiation surface, with light emitted from the light source in a predetermined pattern. In particular, it is desirable that the area irradiated with light by the curing unit 11 (irradiation range) has a surface area that is approximately equal to or slightly larger than the surface area of ​​the pattern region 16a. This is to minimize the irradiation area to prevent expansion of the mold 16 or substrate 17 due to the heat generated by the irradiation, thereby preventing positional shift or deformation of the pattern transferred to the imprint material 18. This is also to prevent light reflected by the substrate 17 and other components from reaching the application unit 15 and solidifying the imprint material 18 remaining in the discharge portion of the application unit 15, thereby preventing malfunctions in the operation of the application unit 15. Examples of light sources include high-pressure mercury lamps, various excimer lamps, excimer lasers, and light-emitting diodes. The light source can be appropriately selected based on the characteristics of the imprint material 18, which is the light-receiving object.

[0025] FIG3 shows an example configuration of the detection device 12. The detection device 12 is configured to optically detect or measure the relative position between a mold mark (first mark) 19 disposed on a mold (first object) 16 and a substrate mark (second mark) 20 disposed on a substrate (second object) 17. The mold mark (first mark) 19 and the substrate mark (second mark) 20 are configured to form optical information representing the relative position in the X direction (first direction) or the Y direction (second direction) on the imaging surface of an image sensor 25 (described later). The detection device 12 may include an illumination system 22 and a detection system 21. The illumination system 22 and the detection system 21 may share some components. The illumination system 22 includes a light source 23 and uses light from the light source 23 to generate illumination light, which is then used to illuminate the measurement target object (the first mark and the second mark). The illumination light may be unpolarized light. The detection system 21 detects the relative position between the mold mark (first mark) 19 and the substrate mark (second mark) 20 as the measurement target object by detecting light from the measurement target object illuminated with the illumination light.

[0026] The optical axis of the inspection device 12 at the location of the substrate 17 and mold 16 is perpendicular to the upper surface of the substrate 17 and the lower surface of the mold 16 (pattern area 16a), that is, parallel to the Z axis. The inspection device 12 can be configured to be driven in the X and Y directions by a drive mechanism (not shown) based on the positions of the mold mark 19 and the substrate mark 20. The inspection device 12 can be configured to be driven in the Z direction to align the focus of the inspection system 21 with the position of the mold mark 19 or the substrate mark 20. The inspection device 12 may include an optical element or optical system for focus alignment. Based on the relative position of the mold mark 19 and the substrate mark 20 detected or measured by the inspection device 12, the positioning of the substrate 17 by the substrate drive mechanism 14 can be controlled, and the shape and magnification of the pattern area 16a by the correction mechanism (not shown) can be corrected. The correction mechanism is mounted on the mold drive mechanism 13 and can adjust the shape and magnification of the pattern area 16a of the mold 16 by deforming the mold 16. The mold mark 19 and the substrate mark 20 will be described in detail later.

[0027] The mold drive mechanism 13 may include a mold chuck (not shown) that holds the mold 16 by vacuum suction or electrostatic force, and a mold drive unit (not shown) that drives the mold 16 by driving the mold chuck. The mold drive mechanism 13 may include the aforementioned alignment mechanism. For example, the mold drive unit may be configured to drive the mold chuck or mold 16 relative to the Z axis. The mold drive unit may further be configured to drive the mold chuck or mold 16 relative to at least one of the θX axis, the θY axis, the θZ axis, the X axis, and the Y axis.

[0028] The substrate drive mechanism 14 may include a substrate chuck that holds the substrate 17 by vacuum suction or electrostatic force, and a substrate drive unit (not shown) that drives the substrate 17 by driving the substrate chuck. For example, the substrate drive unit may be configured to drive the substrate chuck or the substrate 17 relative to the X-axis, the Y-axis, and the θZ-axis. The substrate drive unit may further be configured to drive the substrate chuck or the substrate 17 relative to at least one of the θX-axis, the θY-axis, and the Z-axis.

[0029] The applying unit (dispenser) 15 applies or arranges an uncured imprint material 18 on a substrate 17. The applying unit 15 may be arranged outside the housing of the imprint apparatus 10. In this case, the applying unit 15 may be understood as a component that is not a component of the imprint apparatus 10.

[0030] Mold 16 contains a pattern (such as a circuit pattern) in pattern region 16a to be transferred to substrate 17 (on which imprint material 18 is formed). Mold 16 can be made of a material that transmits light as curing energy, such as quartz. Substrate 17 can be, for example, a semiconductor substrate such as a single crystal silicon substrate, or a substrate comprising at least one layer on a semiconductor substrate.

[0031] The control unit C can be configured to control the curing unit 11, the inspection device 12, the mold drive mechanism 13, the substrate drive mechanism 14, and the application unit 15. The control unit C can be formed, for example, by a field programmable gate array (FPGA), a computer embedded with a program, or a combination of all or some of these components. The FPGA can include a programmable logic device (PLD) or an application-specific integrated circuit (ASIC). The control unit C includes memory and a processor and can define the operation and functions of the imprint apparatus 10 by operating based on arithmetic formulas, parameters, and computer programs stored (saved) in the memory. At least some of the functions of the inspection device 12 (such as the function of processing images captured by the image sensor 25) can be provided by a module incorporated into the control unit C. In this case, the module of the control unit C can be understood as part of the inspection device 12.

[0032] The imprint process or patterning process performed by the imprint apparatus 10 will now be described. First, a substrate 17 is transferred to the substrate chuck of the substrate drive mechanism 14 by a substrate transfer mechanism (not shown) and secured to the substrate chuck. Subsequently, the substrate 17 is driven by the substrate drive mechanism 14, causing the shot area of ​​the substrate 17 to move to the application position of the application unit 15. Thereafter, the application unit 15 applies, arranges, or supplies an imprint material 18 onto the shot area (imprint area) of the substrate (application step).

[0033] Next, the substrate 17 is driven by the substrate drive mechanism 14 so that the shot area, already equipped with the imprint material 18, is positioned directly below the pattern area 16a of the mold 16. Then, for example, the mold drive mechanism 13 lowers the mold 16 so that the imprint material 18 on the substrate 17 and the pattern area 16a of the mold 16 come into contact with each other (contact step). This fills the space between the substrate 17 and the pattern area 16a of the mold 16 (including the recessed portion of the pattern area 16a) with the imprint material 18 (filling step). Furthermore, the detection device 12 is used to detect or measure the relative positions of the mold marks 19 and the substrate marks 20, each formed by a plurality of mark pairs. Based on this result, the pattern area 16a and the shot area of ​​the substrate 17 are aligned (alignment step). At this time, a correction mechanism can be used to correct the shape of the pattern area 16a of the mold 16. Furthermore, a heating mechanism (not shown) can be used to correct the shape of the shot area of ​​the substrate 17.

[0034] When the filling and alignment steps are complete, the curing unit 11 irradiates the imprint material 18 with light through the mold 16, thereby curing the imprint material 18 (curing step). At this point, the detection device 12 can be driven backward to avoid blocking the optical path of the curing unit 11. Subsequently, the mold drive mechanism 13 raises the mold 16 to separate it from the cured imprint material 18 on the substrate 17 (separation step).

[0035] The imprint apparatus 10 can be understood as an example of a lithography apparatus, including a detection device 12, which aligns an original (or pattern area) and a substrate (or shot area) based on output from the detection device 12, and transfers the original pattern onto the substrate. Based on the output from the detection device 12, the imprint apparatus 10 aligns a mold 16 (a first object or original) provided with a mold mark 19 (a first mark) with a substrate 17 (a second object) provided with a substrate mark 20 (a second mark).

[0036] The details of the inspection device 12 will be described below with reference to FIG3 . As described above, the inspection device 12 includes an illumination system 22 and an inspection system 21, and the illumination system 22 and the inspection system 21 may share some components. The illumination system 22 directs illumination light generated by a light source 23 onto a common optical axis via a prism 24, thereby illuminating the mold mark 19 and the substrate mark 20. The light source 23 may include, for example, at least one of a halogen lamp, an LED, a semiconductor laser (LD), a high-pressure mercury lamp, a metal halide lamp, a supercontinuum light source, and a laser-driven light source (LDLS). The wavelength of the illumination light generated by the light source 23 is selected so as not to cure the imprint material 18.

[0037] The illumination system 22 and the inspection system 21 share a prism 24, and the prism 24 can be arranged on or near the pupil surface 1 of the illumination system 22, or on or near the pupil surface 2 of the inspection system 21. Each of the mold mark 19 and the substrate mark 20 can include a mark formed by a diffraction grating. The inspection system 21 can form an optical image of interference light (interference fringes or moiré patterns) on the imaging surface of the image sensor 25. This interference light is generated by the interference between the light diffracted by the mold mark 19 and the substrate mark 20 illuminated by the illumination system 22. The image sensor 25 can be formed, for example, by a CCD sensor or a CMOS sensor.

[0038] The prism 24 includes a surface (joined surface) formed by joining two components as a reflective surface RS, and includes a reflective film 24a on the joined surface. The prism 24 can be replaced by a plate-shaped optical element having the reflective film 24a on its surface. The prism 24 does not need to be located on or near the pupil surface 1 of the illumination system 22, or on or near the pupil surface 2 of the detection system 21. The illumination aperture stop 27 (e.g., a pinhole plate) can be located on the pupil surface 1 of the illumination system 22. The detection aperture stop 26 can be located on the pupil surface 2 of the detection system 21. The illumination aperture stop 27 defines the light intensity distribution on the pupil surface 1 of the illumination system 22. Note that the illumination aperture stop 27 can be any component and can form illumination light parallel to the optical axis by defining the area of ​​the reflective film 24a.

[0039] Figure 4A is a schematic diagram of a mold mark 19 serving as an alignment mark. Figure 4B is a schematic diagram of a substrate mark 20 serving as an alignment mark. Mold mark 19 can be formed, for example, by mark 19a and diffraction gratings 19b and 19b'. Substrate mark 20 can be formed, for example, by mark 20a and diffraction gratings 20b and 20b'. Marks 19a and 20a are coarse detection marks, while diffraction gratings 19b, 19b', 20b, and 20b' are fine detection marks.

[0040] Each diffraction grating 19b, 19b', 20b, and 20b' can include a periodic pattern. The relative position between mold 16 and substrate 17 can be determined from the detection results of detection device 12 based on the geometric center positions of marks 19a and 20a. Since interference fringes (moire) are generated by the diffracted light from diffraction grating 19b (19b') of mold mark 19 and diffraction grating 20b (20b') of substrate mark 20, the amount of light that creates the moire changes depending on the diffraction efficiency of mold mark 19 and substrate mark 20. In particular, since the diffraction efficiency changes periodically depending on the wavelength, there may be wavelengths where the moire can be effectively detected and wavelengths where it is difficult to detect. Light at wavelengths where the moire is difficult to detect may be noise.

[0041] Figures 5A to 5D are diagrams each illustrating an example of a diffraction grating that produces moiré. The principles of generating moiré using diffraction light from diffraction gratings 19b and 20b and detecting the relative position between diffraction gratings 19b and 20b using the moiré will be described below with reference to Figures 5A to 5D. The periods of the patterns (gratings) in the measurement direction of diffraction grating 19b provided in mold 16 and diffraction grating 20b provided in substrate 17 differ slightly from each other. If two diffraction gratings with different periods are superimposed on each other, interference between the light diffracted from the two diffraction gratings creates a pattern with a period reflecting the period difference between the diffraction gratings, known as moiré. Since the phase of the moiré changes depending on the relative position of the diffraction gratings, the relative position between diffraction gratings 19b and 20b, and therefore the relative position between mold 16 and substrate 17, can be determined by detecting the moiré.

[0042] More specifically, if diffraction gratings 19b and 20b with slightly different periods are superimposed on each other, the light diffracted from the diffraction gratings 19b and 20b overlaps, generating moiré patterns with a period that reflects the period difference, as shown in Figure 5C . In the moiré patterns, the positions of bright and dark areas (the phase of the fringes) vary depending on the relative position of the diffraction gratings 19b and 20b. For example, if one of the diffraction gratings 19b and 20b is offset in the X direction, the moiré patterns shown in Figure 5C change to those shown in Figure 5D . Because the moiré patterns are generated as fringes with a larger period by increasing the actual positional offset between the diffraction gratings 19b and 20b, the relative position between the two diffraction gratings 19b and 20b can be detected with high precision, even if the resolution of the detection system 21 is low. The diffraction gratings 19b, 19b', 20b, and 20b' have been described using one-dimensional diffraction grating patterns. However, for example, a checkerboard pattern can be used for the diffraction gratings 20b and 20b', as shown in Figure 6B. By using a checkerboard pattern as the diffraction grating pattern, light can be diffracted not only in the Y direction shown in Figures 4A and 4B but also in the X direction.

[0043] If there is scattered light from pattern edges and from impurities, they can cause measurement errors in moiré measurements. If illumination light enters the alignment mark from the Z direction, which is perpendicular to the XY plane, then noise light passes through both the X and Y axes of the pupil surface 2 of the detection system 21. This is because the edges of the mold mark 19 and substrate mark 20 patterns are parallel to one of the X and Y axes. Therefore, it is preferable that the image sensor 25 detect light that has passed through an area deviated from the center of the pupil of the detection system 21 as the signal required for moiré detection, while blocking noise light entering the pupil of the detection system 21 along the X and Y axes. This can reduce noise caused by scattered light from pattern edges. Furthermore, if both facing sides of the checkerboard pattern are not parallel to either the X or Y axes, scattered light from the pattern edges can pass through axes other than the X and Y axes of the pupil surface 2 of the detection system 21. Therefore, it is desirable that each pattern edge be parallel to one of the X and Y axes. This is not limited to the case where the diffraction grating pattern of the substrate mark 20 is a checkerboard pattern and the diffraction grating pattern of the mold mark 19 is a line and space pattern. For example, the diffraction grating pattern of the substrate mark 20 may be a line and space pattern, and the diffraction grating pattern of the mold mark 19 may be a checkerboard pattern.

[0044] Next, we will describe a method for determining relative position by detecting moiré patterns. Diffraction gratings 19b and 20b are formed from periodic patterns and have slightly different periods in the measurement direction. Therefore, if these diffraction gratings are superimposed on each other, moiré patterns are formed, resulting in light intensity varying in the Y direction. Due to the difference in period between diffraction gratings 19b and 20b, the direction of shift of the moiré patterns varies when the relative position changes. For example, if the period of diffraction grating 19b is slightly larger than that of diffraction grating 20b, if substrate 17 is relatively shifted in the +Y direction, the moiré patterns will also shift in the +Y direction. On the other hand, if the period of diffraction grating 19b is slightly smaller than that of diffraction grating 20b, if substrate 17 is relatively shifted in the +Y direction, the moiré patterns will shift in the -Y direction.

[0045] Diffraction gratings 19b' and 20b' form another moire pattern. The period relationship of diffraction gratings 19b and 20b is opposite to that of diffraction gratings 19b' and 20b'. Therefore, if the relative position changes, the measured positions of the two moire patterns will change in opposite directions. If the periodic marks on the mold and substrate sides that generate the moire pattern are offset by one period, the moire detection principle cannot detect a one-period offset. Therefore, by using marks 19a and 20a with low detection accuracy, it is possible to confirm that there is no relative positional offset between mold 16 and substrate 17 within one period.

[0046] Subsequently, the light intensity distribution on the pupil surface 1 of the illumination system 22 and the pupil surface 2 of the detection system 21 will be described exemplarily with reference to FIG1A and FIG1B . As shown in FIG1A , a light intensity distribution 3 is generated at the exit of the pupil surface 1 of the illumination system 22, with the light intensity concentrated at the intersection of the x-axis and the y-axis (i.e., the optical axis). FIG1B illustrates the light intensity distribution formed on the pupil surface 1 of the detection system 21 by light 4a to 4d, 5a to 5d, and 6 diffracted from diffraction gratings 19b and 20b (19b' and 20b') illuminated by the light intensity distribution 3. The xyz coordinate system is defined as the coordinate system of the pupil surface 1 of the illumination system 22. The x-axis and y-axis of the pupil surface 1 of the illumination system 22 coincide with the Z-axis and Y-axis of the XYZ coordinate system, respectively. The x-direction parallel to the x-axis is conjugate to the x-direction parallel to the x-axis, and the y-direction parallel to the y-axis is conjugate to the y-direction parallel to the y-axis. In the illumination system 22, if the x-direction and the X-direction are conjugate to each other, this means that if there is no reflective surface (e.g., reflective surface RS) between the mold 16 / substrate 17 and the pupil surface 1 of the illumination system 22 that bends the optical axis of the illumination system 22, the x-direction and the X-direction coincide with each other. In the illumination system 22, if the x-direction and the X-direction are conjugate to each other, this means that if there is a reflective surface between the mold 16 / substrate 17 and the pupil surface 1 that bends the optical axis, the x-direction mapped onto the pupil surface 1 by the reflective surface coincides with the x-direction. In the presence of a reflective surface, the x-direction may or may not coincide with the X-direction. The same applies to the conjugation of the y-direction and the Y-direction.

[0047] In the example shown in Figure 3, there are no reflective surfaces between the mold 16 / substrate 17 and the pupil surface 2 of the detection system 21 that would bend the optical axis of the detection system 21. Therefore, if the xyz coordinate system is defined as the coordinate system of the pupil surface 2 of the detection system 21, the x-axis coincides with the X-axis, and the y-axis coincides with the Y-axis. The x-direction (third direction) parallel to the x-axis is conjugated with the X-direction (first direction) parallel to the X-axis, and the y-direction (fourth direction) parallel to the y-axis is conjugated with the Y-direction (second direction) parallel to the Y-axis. In the detection system 21, if the x-direction and the X-direction are conjugated to each other, this means that the x-direction and the X-direction coincide with each other if there are no reflective surfaces between the mold 16 / substrate 17 and the pupil surface 2 of the detection system 21 that would bend the optical axis of the detection system 21. In detection system 21, if the x-direction is conjugate to the X-direction, this means that if a reflective surface that bends the optical axis exists between mold 16 / substrate 17 and pupil surface 2 of detection system 21, the X-direction mapped onto pupil surface 2 by the reflective surface coincides with the x-direction. In the presence of a reflective surface, the x-direction may or may not coincide with the X-direction. The same applies to the conjugation of the y-direction to the Y-direction.

[0048] The case where the measurement direction (the direction of light intensity variation in the moiré pattern) coincides with the X direction (the first direction) will now be described. The relative position between the diffraction grating 19b (19b') of the mold mark 19 and the diffraction grating 20b (20b') of the substrate mark 20 corresponds to the relative position between the mold mark 19 and the substrate mark 20. The detection system 21 forms an image on the imaging surface of the image sensor 25 using information indicating the relative position between the diffraction grating 19b (19b') of the mold mark 19 and the diffraction grating 20b (20b') of the substrate mark 20 in the measurement direction.

[0049] Consider the case where, at the exit point of pupil surface 1 of illumination system 22, light intensity distribution 3 is formed, with light intensity concentrated at and near the intersection of the X-axis and Y-axis (the optical axis of illumination system 22). In other words, the illumination light only passes through the optical axis of illumination system 22 and the vicinity of pupil surface 1 of illumination system 22. In this case, it can be considered that only the light component of the light emitted from light source 23 (parallel to the optical axis) enters mold mark 19 (diffraction gratings 19b and 19b') as illumination light. Mold mark 19 (diffraction gratings 19b and 19b') generates positive first-order diffracted light and negative first-order diffracted light in the X-axis direction. Of the diffracted light generated by mold mark 19 (diffraction gratings 19b and 19b'), positive first-order diffracted light is diffracted in the positive direction of the X-axis relative to the optical axis, while negative first-order diffracted light is diffracted in the negative direction of the X-axis relative to the optical axis. Each diffracted light beam enters substrate marks 20 (diffraction gratings 20b and 20b'), generating positive first-order diffracted light and negative first-order diffracted light. Because substrate marks 20 include a checkerboard pattern, the direction of travel of the light diffracted by substrate marks 20 includes both an X-axis component and a Y-axis component. Of the diffracted light beams generated by substrate marks 20, the positive first-order diffracted light beams are diffracted by a positive component of the Y-axis relative to the optical axis in the direction of travel, while the negative first-order diffracted light beams are diffracted by a negative component of the Y-axis relative to the optical axis in the direction of travel.

[0050] 1A and 1B , for example, on the pupil surface 2 of the detection system 21, the diffracted light 4a represents the light obtained when the illumination light enters the mold mark 19 and is diffracted in the negative first-order direction, and is diffracted in the positive first-order direction at the substrate mark 20. The diffracted light 4a is represented by ( -1, +1). According to this representation, in addition to the diffracted light (-1, +1), diffracted light 4b (+1, +1), diffracted light 4c (-1, -1), and diffracted light 4d (+1, -1) also enter pupil surface 2. The diffracted light 4a and 4b form an image on the imaging surface of image sensor 25, generating interference fringes (moire) whose light intensity varies in the X direction. Similarly, the diffracted light 4c and 4d generate interference fringes whose light intensity varies in the X direction.

[0051] The pitch of the mold marks 19 (19b and 19b') is represented by Pmx, and the pitch of the substrate marks 20 (20b and 20b') in the X and Y directions are represented by Pwx and Pwy, respectively. The distance from the X axis of the diffracted light 4a on the pupil surface 2 of the detection system 21 can be given by f･tanθwy, where f represents the focal length of the lens system arranged between the pupil surface 2 of the detection system 21 and the mold marks 19 / substrate marks 20, and θwy represents the diffraction angle in the Y direction of the substrate marks 20. The diffraction angle θwy is arcsin(λ / Pwy). This is because the diffraction angle θ can be given by sinθ=λ / p, where λ represents the wavelength of light and p represents the mark pitch. The wavelength λ can be, for example, a single wavelength as in the case of using a laser light source, or it can have an intensity distribution within a wavelength band of 500 to 800 nm. On the other hand, the distance of the diffracted light 4a from the Y-axis can be given by f･tan(θmx-θwx), where θmx represents the diffraction angle in the X-axis direction at mold mark 19, and θwx represents the diffraction angle in the X-axis direction at substrate mark 20. θmx-θwx is arcsin(λ / Pmx)-arcsin(λ / Pwx). This is because the light entering mold mark 19 / substrate mark 20 is diffracted in the X-axis direction by each of mold mark 19 and substrate mark 20. Furthermore, when the measurement direction is the same as the Y-axis (second direction) (orthogonal to the X-axis of pupil surface 1 or 2), the same applies to mold mark 19 / substrate mark 20, and the diffracted light 5a, 5b, 5c, and 5d can be described.

[0052] Pattern edge light 6 will be described with reference to FIG7 . Pattern edge light 6 is light diffracted at each edge of the entire pattern of the diffraction gratings 19b (19b') and 20b (20b') of the mold mark 19 and substrate mark 20. Furthermore, the pitch of the edges of the small pattern elements that make up the diffraction gratings 19b (19b') and 20b (20b') is small, so the diffracted light is not detectable. The pattern edge light in the diffraction grating 19b of the mold mark 19 will be described. Light entering the edge of the entire diffraction grating 19b is diffracted only in the axial direction orthogonal to the edge. This is because the edge of the entire diffraction grating 19b is parallel to one of the X-axis and the Y-axis. For example, if light enters the edge in a direction parallel to the X-axis, the diffracted light is in a direction parallel to the Y-axis. On the other hand, if light enters the edge in a direction parallel to the Y-axis, the light is diffracted in a direction parallel to the X-axis. The same applies to the light diffracted from the diffraction grating 19b' of the mold mark 19 and the diffraction gratings 20b and 20b' of the substrate mark 20. Therefore, the pattern edge light 6 passes through the X axis and its vicinity and the Y axis and its vicinity on the pupil surface 2 of the detection system 21.

[0053] The illumination aperture stop 27 and detection aperture stop 26, which are used to remove unnecessary pattern edge light 6, will be described with reference to Figures 8A and 8B. To allow light parallel to the optical axis to enter the mold mark 19, it is desirable to create a light intensity distribution at the exit of the pupil surface 1 of the illumination system 22 so that the light intensity is concentrated only at and near the intersection of the X-axis and Y-axis (i.e., the optical axis). To achieve this, an illumination aperture stop 27 (pinhole plate) with an opening (pinhole) at the intersection of the X-axis and Y-axis can be placed on the pupil surface 1. This allows only light parallel to the optical axis of the light source 23 to enter the mold mark 19 (diffraction gratings 19b and 19b').

[0054] The diffracted light 4a to 4d and 5a to 5d (which forms moiré patterns on the imaging surface of the image sensor 25) enters an area of ​​the pupil surface 2 of the detection system 21 that is not on the X-axis and Y-axis. On the other hand, pattern edge light 6 enters the pupil surface 2 of the detection system 21 in the vicinity of the X-axis and in the vicinity of the Y-axis. When the relative position between the diffraction gratings 19b (19b') and 20b (20b') is measured using the moiré phase difference, pattern edge light 6 becomes noise light. To address this issue, a detection aperture stop 26 including a light shield 260 is disposed in the vicinity of the X-axis and in the vicinity of the Y-axis on the pupil surface 2 of the detection system 21, thereby shielding the pattern edge light 6.

[0055] The light shield 260 disposed on the pupil surface 2 of the detection system 21 can include a first light shielding portion 261 that intersects the optical axis of the detection system 21 in a direction parallel to the x-axis (third direction), and a second light shielding portion 262 that intersects the optical axis of the detection system 21 in a direction parallel to the y-axis (fourth direction). The light shield 260 can also include a third light shielding portion 263 aligned with the optical axis. The third light shielding portion can have a circular shape. As described above, the direction parallel to the x-axis (third direction) is conjugate with the direction parallel to the X-axis (first direction), and the direction parallel to the y-axis (fourth direction) is conjugate with the direction parallel to the Y-axis (second direction). The illumination aperture stop 27 is a pinhole plate containing a pinhole of diameter d.

[0056] The pupil surface 2 of the detection system 21 includes a light-transmitting region 265 in an area where the light-blocking member 260 is not disposed. Light diffracted from the mold marks 19 (19b and 19b') and substrate marks 20 (20b and 20b') illuminated by the illumination light passes through the light-transmitting region 265, thereby forming optical information indicating the relative position between the mold 16 and substrate 17 on the imaging surface of the image sensor 25. Unnecessary light that does not contain optical information indicating the relative position of the light from the mold marks 19 (19b and 19b') and substrate marks 20 (20b and 20b') illuminated by the illumination light is blocked by the first light-blocking portion 261 and the second light-blocking portion 262.

[0057] If the diameter of the concentrated light intensity portion (i.e., the pinhole) in the light intensity distribution 3 formed at the exit point of the pupil surface 1 of the illumination system 22 is represented by d, the width of the pattern edge light 6 on the pupil surface 2 of the detection system 21 is also d. Therefore, to block the pattern edge light 6, the width D of the first light shielding portion 261 and the second light shielding portion 262 of the detection aperture stop 26 is preferably equal to or greater than d. The diffracted light 4a to 4d and 5a to 5d used to form an image on the imaging surface of the image sensor 25 by the moiré pattern need to enter an area outside the light shield 260 on the pupil surface 2 of the detection system 21. For example, for the diffracted light 4a, the distance |f·tanθwy| from the X-axis and the distance |f·tan(θmx-θwx)| from the Y-axis are preferably greater than the sum of half the width D of the light shield 260 and the radius r of the diffracted light 4a on the pupil surface 2 of the detection system 21. In this example, the width D of the light shielding body 260 is the width of the second light shielding portion 262 in the X direction relative to the X direction, and the width of the first light shielding portion 261 in the Y direction relative to the Y direction. If this condition is expressed as a formula, the width D of the light shielding body 260 preferably satisfies the following expression.

[0058] In this example, r is greater than d because the number of pitches of the mold mark 19 and the substrate mark 20 is infinite. For example, in the case of the diffracted light 5a, the width D of the light shield preferably satisfies the following formula.

[0059] In addition, the mark that generates the diffracted light 5a is a mark whose measurement direction is the Y direction.

[0060] The effect of the presence or absence of pattern edge light 6 on moiré phase difference measurement will be described with reference to Figures 9A and 9B. As shown in an arbitrary cross-section 31 along the measurement direction of a moiré pattern containing pattern edge light 6, if pattern edge light 6 is present at each edge of the moiré pattern, it becomes a noise component, reducing the relative phase measurement accuracy. The closer the moiré pattern is to the pattern edge light 6, the greater the impact of this noise component. Therefore, it is difficult to reduce the size of the alignment mark. On the other hand, as shown in an arbitrary cross-section 32 along the measurement direction of the moiré pattern (from which pattern edge light 6 has been removed), if only a moiré signal is present, the relative phase measurement accuracy is improved. Furthermore, when the injection noise of the image sensor 25 is reduced, the relative phase measurement accuracy is also expected to improve.

[0061] Next, a method for manufacturing an article using the imprint apparatus described in the above embodiment will be described. The article may be, for example, a semiconductor device, a display device, or a MEMS device. The article manufacturing method may include a transfer step of transferring the pattern of an original article to a substrate using a lithography apparatus or an imprint apparatus; and a processing step of processing the substrate to obtain an article from the substrate after the transfer step. The transfer step may include a contact step of bringing the mold 16 and the imprint material 18 on the shot area of ​​the substrate 17 into contact with each other. The transfer step may also include a measurement step of measuring the relative position between the mold 16 and the shot area (or substrate mark) of the substrate 17. The transfer step may also include an alignment step of aligning the mold 16 and the shot area of ​​the substrate 17 based on the results of the measurement step. The transfer step may also include a curing step of curing the imprint material 18 on the substrate 17 and a separation step of separating the imprint material 18 from the mold 16. This forms or transfers a pattern made from the cured imprint material 18 on the substrate 17. The processing steps may include, for example, etching, resist stripping, dicing, bonding, and packaging.

[0062] The patterns created by the cured product formed using the imprinting equipment are used permanently on at least some of a variety of items, or temporarily during the manufacture of various items. These items include circuit components, optical components, MEMS, recording components, sensors, molds, and the like. Examples of circuit components include volatile and non-volatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, as well as semiconductor components such as LSIs, CCDs, image sensors, and FPGAs. Examples of molds include those used for imprinting.

[0063] The pattern of the cured product is directly used as a component of at least some of the above-mentioned articles or temporarily used as a resist mask. After etching or ion implantation in the substrate processing step, the resist mask is removed.

[0064] Next, we will describe a method for manufacturing an article in which an imprint device forms a pattern on a substrate, processes the patterned substrate, and manufactures an article from the processed substrate. As shown in Figure 10A, a substrate 1z, such as a silicon wafer, is prepared, with a processing material 2z, such as an insulator, formed on its surface. Next, an imprint material 3z is applied to the surface of the processing material 2z using an inkjet method or other method. This diagram shows the imprint material 3z being applied to the substrate as a plurality of droplets.

[0065] As shown in Figure 10B, a mold 4z, imprinted with a concave-convex pattern, faces the imprint material 3z on the substrate. As shown in Figure 10C, the substrate 1z, to which the imprint material 3z has been applied, is brought into contact with the mold 4z, and pressure is applied. The gap between the mold 4z and the workpiece 2z is filled with the imprint material 3z. In this state, when the imprint material 3z is irradiated with light serving as curing energy through the mold 4z, the imprint material 3z is cured.

[0066] As shown in FIG10D , after the imprint material 3z is cured, the mold 4z is separated from the substrate 1z, and a pattern of the cured product of the imprint material 3z is formed on the substrate 1z. In the pattern of the cured product, the concave portions of the mold correspond to the convex portions of the cured product, and the convex portions of the mold correspond to the concave portions of the cured product. In other words, the concave-convex pattern of the mold 4z is transferred to the imprint material 3z.

[0067] As shown in FIG10E , when etching is performed using the cured product pattern as an etch resist mask, portions of the surface of the process material 2z where the cured product is absent or thin are removed, forming recesses 5z. As shown in FIG10F , when the cured product pattern is removed, an article having recesses 5z formed in the surface of the process material 2z is obtained. Here, the cured product pattern is removed. However, instead of removing the cured product pattern after this process, the cured product pattern can be used as an interlayer dielectric film, for example, incorporated into a semiconductor device, or a component of an article.

[0068] Although the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0069] 1: Pupil surface 2: Pupil surface 3: Light intensity distribution 4a:Light 4b:Light 4c: Light 4D: Light 5a: Light 5b: Light 5c: Light 5d: Light 6: Light 10: Imprinting equipment 11: Curing unit 12: Detection device 13:Mold drive mechanism 14: Substrate drive mechanism 15: Application unit 16:Mold 16a: Pattern area 17:Substrate 18: Embossed material 19:Mold marking 19a: Marking 19b: Diffraction grating 19b': Diffraction grating 20: Substrate marking 20a: Marking 20b: Diffraction grating 20b': Diffraction grating 21: Detection system 22: Lighting system 23: Light Source 24: Prism 24a: Reflective film 25: Image sensor 26: Detecting the aperture diaphragm 27: Illumination aperture diaphragm 31: Any cross section 32: Any cross section 1z:Substrate 2z: Processing Materials 3z: embossing material 4z:Mold 5z: Groove 260:Light shield 261: First light shielding part 262: Second light shielding part 263: Third light shielding part 265: light-transmitting area d: diameter ES: Reflective Surface C: Control Unit D: Width

Claims

1. A detection device for detecting the relative position between a first mark and a second mark respectively provided in a first object and a second object arranged overlapping each other, comprising: A lighting system configured to illuminate the first and second marks with lighting light; The system includes an image sensor and an imaging surface of the image sensor configured to form an image by light diffracted from the first and second marks illuminated by the illumination system. The first and second marks are configured to form optical information on the imaging surface indicating their relative positions in a first direction or a second direction orthogonal to the first direction. The illumination light is light that passes only through the optical axis of the illumination system and light near the optical axis on the pupil surface of the illumination system. A light-shielding body includes a first light-shielding portion intersecting the optical axis of the detection system in a direction parallel to a third direction and a second light-shielding portion intersecting the optical axis of the detection system in a direction parallel to a fourth direction. The light-shielding body is provided on the pupil surface of the detection system, and the third direction is conjugate to the first direction, and the fourth direction is conjugate to the second direction.

2. The apparatus as claimed in claim 1, wherein, The lighting system includes a pinhole plate disposed on the surface of the pupil of the lighting system, and the lighting light is light passing through the pinholes of the pinhole plate.

3. The apparatus as claimed in claim 2, wherein, The width of the first light-blocking portion in the fourth direction and the width of the second light-blocking portion in the third direction are not less than the diameter of the pinhole.

4. The apparatus as claimed in claim 2, wherein, The lighting system and the detection system share a prism, and the pupil surface of the lighting system is disposed between the light source and the prism, and the first mark and the second mark are illuminated by the reflection of the lighting light by the prism.

5. The apparatus as claimed in claim 4, wherein, The light diffracted from the first mark and the second mark passes through the prism and enters the imaging surface, and the pupil surface of the detection system is disposed between the prism and the imaging surface.

6. The apparatus as claimed in claim 1, wherein, The first light-blocking portion extends in diameter in the third direction of the pupil surface of the detection system, and the second light-blocking portion extends in diameter in the fourth direction of the pupil surface of the detection system.

7. The apparatus of claim 1, wherein, The pupil surface of the detection system includes a light-transmitting area in the region where the light shield is not configured, and the light diffracted from the first and second marks illuminated by the illumination light passes through the light-transmitting area to form optical information indicating the relative position on the imaging surface.

8. The apparatus as claimed in claim 7, wherein, Light diffracted from the first mark and the second mark, which are illuminated by the illumination light, passes through the light-transmitting area to form optical information indicating the relative position on the imaging surface.

9. The apparatus of claim 1, wherein, The light-shielding body also includes a third light-shielding portion aligned with the optical axis of the detection system.

10. The apparatus of claim 1, wherein, The illumination light is unpolarized light.

11. The apparatus of claim 1, wherein, In the light from the first and second marks illuminated by the illumination light, unwanted light that does not contain optical information indicating the relative position is blocked by both the first and second light-blocking portions.

12. A lithography apparatus for transferring a pattern from an original object to a substrate, comprising: The detection device as defined in any one of claims 1 to 11, wherein the lithography device is configured to align the original object with a first mark as the first object and the substrate with a second mark as the second object based on the output from the detection device.

13. The equipment as requested in item 12, wherein, The lithography equipment is designed to be used as an imprinting device.

14. A method for manufacturing an article, comprising: The pattern of the original object is transferred to the substrate using the lithography apparatus defined in claim 13; And to process the substrate in order to obtain an article from the substrate after the transfer.

Images