Detection apparatus, lithography apparatus, and article manufacturing method

Abstract

The detection device includes an imaging element having an imaging surface having a first periodic structure; and an optical system configured to illuminate a detection target having a second periodic structure different from the first periodic structure and to form an image of light from the detection target on the imaging surface. Light incident on the imaging surface generates a plurality of diffracted light beams of different orders according to the first periodic structure. The normal of the imaging surface is tilted with respect to the optical axis such that the optical axis of the optical system is located between diffracted light beams of at least one order of adjacent orders among the plurality of diffracted light beams.

Description

Technology Field

[0001] The present invention relates to a detection device, a lithography device, and a method for manufacturing an article. Background Technology

[0002] Japanese Patent Publication No. 2021-004940 describes an imaging element that detects a moiré pattern generated by a mold mark provided on a mold and a substrate mark provided on a substrate, and obtains a relative position between the mold mark and the substrate mark based on an image of the moiré pattern.

[0003] An imaging element includes a pixel array formed by a periodic array of multiple pixels. Accordingly, the imaging surface of the imaging element has a periodic structure. The periodic structure generates diffracted light, and the diffracted light causes noise components in the image detected by the imaging element. Noise components can reduce the detection accuracy of the detection device. The problem to be solved

[0004] The present invention provides a technology advantageous for suppressing the degradation of detection accuracy caused by the periodic structure of an imaging element. means of solving the problem

[0005] One aspect of the present invention provides a detection device comprising: an imaging element having an imaging surface having a first periodic structure; and an optical system configured to illuminate a detection target having a second periodic structure different from the first periodic structure and to form an image of light from the detection target on the imaging surface, wherein the light incident on the imaging surface generates a plurality of diffracted light beams of different orders according to the first periodic structure, and the normal of the imaging surface is tilted with respect to the optical axis such that the optical axis of the optical system is located between diffracted light beams of one or more adjacent orders among the plurality of diffracted light beams.

[0006] Other features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Brief explanation of the drawing

[0007] FIG. 1 is a drawing illustrating an exemplary arrangement of an imprint device according to one embodiment. FIGS. 2a and FIGS. 2b are drawings illustrating an exemplary arrangement of a detection device according to a first embodiment. FIGS. 3a and 3b are drawings for illustrating a diffracted light beam reflected from an imaging element having an imaging surface including a periodic structure. Figures 4a and 4b are diagrams illustrating a diffracted light beam reflected from an imaging element when the imaging element is tilted. FIGS. 5a to 5c are drawings for explaining a method of determining an inclination angle by considering the NA of a detection optical system. FIG. 6 is a drawing illustrating an exemplary arrangement of a detection device according to a second embodiment. FIGS. 7a to 7f are drawings illustrating an exemplary method of manufacturing an article. Specific details for implementing the invention

[0008] Hereinafter, embodiments are described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are not intended to limit the scope of the claimed invention. While many features are described in the embodiments, the invention is not limited to requiring all such features, and many such features may be appropriately combined. Additionally, in the accompanying drawings, the same reference numerals are assigned to identical or similar components, and redundant descriptions thereof are omitted.

[0009] One aspect of the present invention relates to a detection device comprising an imaging element having an imaging surface having a first periodic structure, and an optical system configured to illuminate a detection target having a second periodic structure different from the first periodic structure and to form an image of light from the detection target on the imaging surface. The second periodic structure of the detection target may be formed, for example, by a first pattern provided on a first object and a second pattern provided on a second object arranged to overlap with the first object. The first pattern and the second pattern may generate a moiré pattern corresponding to the relative positions of the first pattern and the second pattern. Alternatively, the second periodic structure of the detection target may be formed by alignment marks provided on the object.

[0010] Another aspect of the present invention relates to a lithography apparatus for transferring a pattern of a plate onto a substrate. The lithography apparatus may include the aforementioned detection device provided for alignment between the plate and the substrate, and a control unit configured to control the alignment between the plate and the substrate based on the output of the detection device. The lithography apparatus may be a drawing device, such as, for example, an imprint device, an exposure device, or an electron beam drawing device. In the following description, an imprint device and a detection device that can be integrated into the imprint device will be described exemplarily as an application of the present invention.

[0011] An imprint device may be configured to form a pattern formed from the cured imprint material on a substrate by bringing an imprint material placed on a substrate and a mold (disk) into contact with each other and applying curing energy to the imprint material to cure the imprint material.

[0012] As an imprint material, a curable composition (also referred to as an uncured resin) that is cured by receiving curing energy is used. Examples of curing energy include electromagnetic waves, heat, etc. Electromagnetic waves may be light selected from a wavelength range of, for example, 10 nm (inclusive) to 1 mm (inclusive), such as infrared, visible light, or ultraviolet light. The curable composition may be a composition that is cured by light irradiation or heating. Among the compositions, the photocurable composition that is cured by light irradiation contains at least a polymerizable compound and a photopolymerization initiator, and may further contain a non-polymerizable compound or a solvent as needed. The non-polymerizable compound is at least one material selected from the group comprising sensitizers, hydrogen donors, internal release agents, surfactants, antioxidants, and polymer components. The imprint material may be disposed on a substrate in the form of droplets or in the form of islands or films formed by connecting multiple droplets by an imprint material supply device (not shown). The viscosity of the imprint material (viscosity at 25°C) may be, for example, 1 mPa·s (inclusive) to 100 mPa·s (inclusive). As a material for the substrate, for example, glass, ceramic, metal, semiconductor, resin, etc., may be used. A member made of a material different from the substrate may be provided on the surface of the substrate as needed. The substrate is, for example, a silicon wafer, a compound semiconductor wafer, or silica glass.

[0013] FIG. 1 illustrates an exemplary arrangement of an imprint device (100) according to one embodiment. In the specification and drawings, directions will be indicated by an xyz coordinate system in which a horizontal plane is set as the xy plane. Generally, a substrate (W), such as a wafer, is placed on a substrate stage (162) such that the surface of the substrate (W) is parallel to the horizontal plane (xy plane). Accordingly, in the specification and drawings, directions orthogonal to each other in the plane following the surface of the substrate (W) are the x-axis and the y-axis, and directions perpendicular to the x-axis and the y-axis are the z-axis. Additionally, directions parallel to the x-axis, y-axis, and z-axis of the xyz coordinate system are referred to as the x-direction, y-direction, and z-direction, respectively, and the direction of rotation around the x-axis, the direction of rotation around the y-axis, and the direction of rotation around the z-axis are referred to as the θx-direction, θy-direction, and θz-direction, respectively.

[0014] In one example, the imprint device (100) is a UV photocuring imprint device that cures the imprint material by irradiating it with UV light (ultraviolet light). However, the imprint device (100) may be an imprint device that cures the imprint material by irradiating it with light of a different wavelength range, or an imprint device that cures the imprint material by other energy (e.g., heat).

[0015] The imprint device (100) may be configured to form a pattern on each of a plurality of shot areas on a substrate (W) by repeating an imprint process. The imprint process may be a process of forming a pattern on one shot area on the substrate (W) by curing the imprint material (R) while the pattern area of ​​the mold (M) is in contact with the imprint material (R) placed on the substrate (W).

[0016] The imprint device (100) may include, for example, a curing unit (120), a mold manipulation mechanism (130), a mold shape correction mechanism (140), a substrate driving unit (160), a detection device (170), a supply unit (190), an observation scope (193), and a control unit (180). Although not illustrated, the imprint device (100) may include a bridge plate supporting the mold manipulation mechanism (130), a base plate supporting the substrate driving unit (160), etc.

[0017] The curing unit (120) can cure the imprint material (R) by irradiating ultraviolet light onto the imprint material (R) on the substrate (W) through the mold (M). In this case, the imprint material (R) may be a UV-curing resin. The curing unit (120) may include, for example, a light source unit (121), an optical system (122), and a half mirror (123). The light source unit (121) may include, for example, a light source such as a mercury lamp that generates ultraviolet light (e.g., i-rays or g-rays) and an elliptical mirror that concentrates the light generated by the light source.

[0018] The optical system (122) may include, for example, a lens, an aperture, and others used to apply light to the imprint material (R) on the shot area to cure the imprint material (R). Light passing through the optical system (122) may be reflected by a half mirror (123) and applied to the imprint material (R). The aperture is used to control the field of view and to control ambient light shielding. Controlling the field of view enables illumination only of the target shot area. Controlling ambient light shielding enables limiting the irradiation of ultraviolet light beyond the target shot area. The optical system (122) may include an optical integrator to uniformly illuminate the mold (M). Light whose range is defined by the aperture strikes the imprint material (R) on the substrate (W) through the optical system (122) and the mold (M). A pattern, such as a circuit pattern of a device, is formed in the pattern area of ​​the mold (M). The material of the mold (M) is, for example, quartz that can transmit ultraviolet rays.

[0019] The mold operating mechanism (130) may include, for example, a mold chuck (131) that holds and supports the mold (M), a mold driving mechanism (132) that drives the mold (M) by driving the mold chuck (131), and a mold base (133) that supports the mold driving mechanism (132). The mold driving mechanism (132) may include a positioning mechanism that controls the position of the mold (M) with respect to six axes, and a mechanism that brings the mold (M) into contact with an imprint material (R) on a substrate (W) and separates the mold (M) from the cured imprint material (R). The six axes are the x, y, z, θx, θy, and θz directions.

[0020] A mold shape correction mechanism (140) may be mounted on a mold chuck (131). The mold shape correction mechanism (140) may correct the shape of the mold (M) (its pattern area) by applying pressure to the outer side of the mold (M) using an actuator, such as a cylinder or a piezo element, which is operated by a fluid such as air or oil, for example. Alternatively, the mold shape correction mechanism (140) may include a temperature control unit that controls the temperature of the mold (M) and correct the shape of the mold (M) (pattern area) by controlling the temperature of the mold (M). The substrate (W) may be deformed (typically, expanded or contracted) through a process such as annealing. Depending on this deformation of the substrate (W), the mold shape correction mechanism (140) may correct the shape of the mold (M) such that the overlap error between the pattern of the mold (M) and the existing pattern on the substrate (W) is within an allowable range.

[0021] The substrate driving unit (160) may include, for example, a substrate chuck (161), a substrate stage (162), a reference mark table (191), and a stage driving mechanism (not shown). The substrate chuck (161) may hold and support the substrate (W) by suction. The substrate stage (162) supports the substrate chuck (161) and moves the substrate (W) by driving the substrate chuck (161). A reference mark (192) is placed on the reference mark table (191). The stage driving mechanism (not shown) may include a positioning mechanism that controls the position of the substrate (W) by controlling the position of the substrate stage (162) with respect to the six axes mentioned above.

[0022] The detection device (170) may be formed as a device configured to detect the relative position (position misalignment) between the shot area on the mold (M) and the substrate (W). In another aspect, the detection device (170) may be formed as a device configured to detect the relative position (position misalignment) between the alignment mark provided on the mold (M) and the alignment mark provided on the shot area on the substrate (W). The detection device (170) may be configured, for example, to illuminate the alignment mark (182) provided on the mold (M) and the alignment mark (183) provided on the substrate (W) and to detect (detect) the interference pattern (moiré pattern) formed by the light diffracted by the two alignment marks. The control unit (180) may detect the relative position of the two alignment marks based on the image detected by the detection device (170). This function of the control unit (180) may be integrated into the detection device (170). The detection device (170) can be used to detect at least one of the position of a mark provided on the mold (M) and the position of a mark provided on the shot area on the substrate (W).

[0023] The supply unit (190) may be formed as a dispenser that supplies an imprint material (R) onto a substrate (W). The supply unit (190) may include a tank that stores the imprint material (R), a nozzle that discharges the imprint material (R) supplied from the tank through a supply path onto the substrate (W), a valve provided in the supply path, and a supply amount control unit.

[0024] The observation scope (193) is a scope for observing the shot area and includes an imaging element for detecting the shot area. The observation scope (193) can be used, for example, to check the contact state between the mold (M) and the imprint material (R) and the progress of filling the imprint material (R) into the recess of the pattern provided in the pattern area of ​​the mold (M).

[0025] The imprint processing performed by the imprint device (100) is described. First, under the control of the control unit (180), a substrate transport device (not shown) transports a substrate (W) onto a substrate chuck (161), and the substrate (W) is fixed onto the substrate chuck (161). Next, under the control of the control unit (180), a stage driving mechanism moves the substrate stage (162) so that the shot area is positioned directly below the mold (M). Next, under the control of the control unit (180), a mold driving mechanism (132) lowers the mold (M) to bring the mold (M) into contact with the imprint material (R) on the substrate (W) (contact step). When the mold (M) comes into contact with the imprint material (R), the imprint material (R) flows along the surface of the pattern area of ​​the mold (M) and fills the space between the pattern area and the substrate (W) and the recess of the pattern provided in the pattern area. Additionally, when the mold (M) and the imprint material (R) are in contact with each other, the detection device (170) can detect (detect) an image formed by diffracted light reflected from the alignment mark (182) on the mold (M) and the alignment mark (183) on the substrate (W). Based on the output (image) of the detection device (170), the control unit (180) can perform alignment between the mold (M) and the substrate (W) by driving the substrate stage (162), shape correction of the pattern area of ​​the mold (M) by the mold shape correction mechanism (140), etc. After that, under the control of the control unit (180), the curing unit (120) applies ultraviolet light from the back surface (upper surface) of the mold (M) and cures the imprint material (R) by the ultraviolet light that has passed through the mold (M) (curing step). Subsequently, under the control of the control unit (180), the mold driving mechanism (132) drives the mold (M) upward to separate the mold (M) from the cured imprint material (R) (mold separation step). Thus, the pattern of the mold (M) is transferred to the imprint material (R) on the substrate (W).

[0026] FIG. 2a is a perspective view illustrating the arrangement of a detection device (170) according to a first embodiment, and FIG. 2b is a yz cross-sectional view of the detection device (170) shown in FIG. 2a. To simplify the description of the optical system, FIG. 2a shows only an optical system that performs measurements in a single direction (e.g., x direction). In FIG. 1, the direction of light emitted from the detection device (170) is changed by a mirror (179), and then the light illuminates alignment marks (182, 183). However, for convenience of explanation, the mirror (179) is not shown in FIG. 2a and FIG. 2b.

[0027] The detection device (170) may include a light source (200), an illumination optical system (IL), and a detection optical system (DL). The illumination optical system (IL) may be configured to illuminate, for example, an alignment mark (182) placed on a mold (M) and an alignment mark (183) placed on a substrate (W). In this example, the alignment marks (182, 183) function as detection targets. In addition to being targets for image detection, the detection targets function as targets for relative position detection or position detection. The illumination optical system (IL) may be configured to perform dipole illumination, in which the detection targets are illuminated by illumination light containing two poles on the pupil surface of the illumination optical system (IL). For example, the illumination optical system (IL) may include a diffractive optical element (171), a lens (173), an aperture diaphragm (174) having two openings for implementing dipole illumination, two polarizing elements (185), and a beam splitter (175). A diffracting optical element (171) can diffract light from a light source (200) toward two openings of an aperture (174). Two polarizing elements (185) may each be provided to correspond to two openings of the aperture (174), and may be arranged so that the polarization directions of the light beams from the two polarizing elements are orthogonal to each other. For example, when a polarizer is used as a polarizing element, the polarizers may be arranged so that the transmission axes of the polarizers are orthogonal to each other. The detection optical system (DL) may include, for example, a lens (176), a beam splitter (175), a lens (177), and an imaging element (178).

[0028] As schematically illustrated in FIG. 3b, the imaging element (178) has an imaging surface (IS) comprising a first periodic structure. The first periodic structure may inevitably be formed by, for example, a microlens array, a light-shielding film, etc. In the example illustrated in FIG. 3b, the first periodic structure has a period (pitch) (p) in each of the x direction and the y direction. An illumination optical system (IL) and an imaging optical system (DL) form an optical system configured to illuminate a detection target and form an image of light from the detection target on the imaging surface (IS) of the imaging element (178). The detection target may include a second periodic structure different from the first periodic structure. In this example, the second periodic structure of the detection target is formed by an alignment mark (183) (first pattern) provided on a substrate (W) and an alignment mark (182) (second pattern) provided on a mold (M) arranged to overlap with the alignment mark (183). The substrate (W) is an example of a first object, and the mold (M) is an example of a second object. The alignment mark (183) may include a periodic structure different from the first periodic structure, and the alignment mark (182) may also include a periodic structure different from the first periodic structure.

[0029] Light incident on the imaging surface (IS) of the imaging element (178) generates multiple diffracted light beams of different orders according to the first periodic structure of the imaging surface (IS). The normal (N) of the imaging surface (IS) is tilted at an angle of inclination (θ) with respect to the optical axis (AX) so that the optical axis (AX) of the optical system (here, attention should be paid only to the detection optical system (DL)) is positioned between adjacent diffracted light beams among the multiple diffracted light beams. In one example, the angle of inclination (θ) of the normal (N) of the imaging surface (IS) with respect to the optical axis (AX) is the angle between the optical axis (AX) and the normal (N) of the imaging surface (IS) in the xz plane.

[0030] The method for determining the tilt angle (θ) is described in detail below. FIG. 3a is a schematic enlarged view of the part of the detection optical system (DL) including the lens (177) and the imaging element (178) when the tilt angle (θ) = 0. As schematically illustrated in FIG. 3b, the imaging plane (IS) of the imaging element (178) includes a first periodic structure. As schematically illustrated in FIG. 3a, light incident on the imaging plane (IS) of the imaging element (178) through the lens (177) generates a plurality of diffracted light beams of different orders according to the first periodic structure. Some of these diffracted light beams return to the detection optical system (DL) and may generate interference patterns and / or flares. If the wavelength of the illumination light generated by the light source (200) is λ and the period (pitch) of the first periodic structure is p, the diffraction angle (θdifn) of the n-th order diffracted light beam is expressed as follows:

[0031] ...(1)

[0032] Here, n is an integer and may include negative values. In FIG. 3a, the counterclockwise direction is defined as the positive direction, but generality is not lost even if the clockwise direction is defined as the positive direction. Since the diffracted light beam as described above is added to the image (moiré pattern) as the image detection target of the imaging element (178), the detection accuracy of the relative positions of the alignment marks (183, 182), i.e., the alignment measurement accuracy, may be reduced. Therefore, the tilt angle (θ) is determined to prevent the diffracted light beam from returning from the imaging plane (IS) to the detection optical system (DL). FIG. 4a illustrates a zero-order diffracted light beam when the tilt angle (θ) is greater than 0. FIG. 4b illustrates multiple orders of diffracted light beams. The direction of propagation of the n-th order diffracted light beam is expressed by the following equation:

[0033] ...(2)

[0034] In order to prevent the diffracted light beam diffracted by the imaging plane (IS) from returning to the detection optical system (DL), an inclination angle (θ) is determined such that the optical axis (AX) of the detection optical system (DL) is positioned between adjacent order diffracted light beams (here, the -n-th order diffracted light beam and the -(n+1)-th order diffracted light beam) among a plurality of diffracted light beams. Here, it is preferable that the inclination angle (θ) be determined such that the bisector between the optical paths of adjacent order diffracted light beams (here, the -n-th order diffracted light beam and the -(n+1)-th order diffracted light beam) overlaps with the optical axis (AX) of the optical system. That is, it is preferable that the average angle of the diffraction angle of the -n-th order diffracted light beam and the diffraction angle of the -(n+1)-th order diffracted light beam coincides with the inclination angle (θ). This can be expressed as follows.

[0035] ...(3)

[0036] By transforming Equation (3), the slope angle (θ) is expressed as follows:

[0037] ...(4)

[0038] Here, as illustrated exemplarily in FIG. 3b, the imaging element (178) is typically periodic in two mutually orthogonal directions. With this in mind, the normal (N) of the imaging plane (IS) can be inclined with respect to the optical axis (AX) so that the imaging element (178) pivots around an axis parallel to the diagonal direction of FIG. 3b (e.g., a direction of 45° with respect to the y-axis and z-axis). In this case, p in equations (1) through (3) can be replaced with (√2)p.

[0039] In addition, considering that the imaging plane (IS) of the imaging element (178) has a two-dimensional first periodic structure, the inclination angle (θ) can be determined as follows. First, the first periodic structure is defined to include a first structure having periodicity in a first direction (e.g., y direction) orthogonal to the normal (N), and a second structure having periodicity in a second direction (e.g., z direction) orthogonal to the normal (N) and the first direction. In this case, light incident on the imaging plane (IS) can generate a plurality of first diffracted light beams of different orders according to the first structure and a plurality of second diffracted light beams of different orders according to the second structure. Accordingly, the inclination angle (θ) of the normal (N) of the imaging plane (IS) can be determined such that the optical axis (AX) of the detection optical system (DL) is positioned between adjacent first diffracted light beams among a plurality of first diffracted light beams and between adjacent second diffracted light beams among a plurality of second diffracted light beams.

[0040] Additionally, it is preferable that the diffracted light beam from the imaging plane (IS) of the imaging element (178) does not return to the NA of the detection optical system (DL) (i.e., the pupil area of ​​the detection optical system (DL)). That is, the inclination angle (θ) of the normal (N) of the imaging plane (IS) with respect to the optical axis (AX) of the detection optical system (DL) can be determined so that an adjacent order of diffracted light beam among the multiple orders of diffracted light beams generated by the imaging plane (IS) travels toward the outside of the NA of the imaging optical system (DL). The NA of the detection optical system (DL) can be defined, for example, by an aperture (not shown) provided in the detection optical system (DL). The aperture can be provided within the beam splitter (175) or placed between the beam splitter (175) and the lens (177).

[0041] Conditions for preventing the diffracted light beam generated by the imaging plane (IS) from returning to the NA of the imaging optical system (DL) will be explained below with reference to FIGS. 5a to 5c. FIG. 5a illustrates a state in which the bisector between the -n-th order diffracted light beam and the -(n+1)-th order diffracted light beam is located on the optical axis (AX), i.e., a state in which Equation (4) holds. If the NA of the detection optical system (DL) is denoted as NAdet, the corresponding angle (θ det ) is expressed as follows:

[0042] ...(5)

[0043] FIG. 5b shows the minimum value of the tilt angle (θ) such that the optical axis (AX) is positioned between the -n-th order diffracted light beam and the -(n+1)-th order diffracted light beam, preventing the diffracted light beam from returning into the NA of the detection optical system (DL). The tilt angle (θ) is expressed as follows:

[0044] ...(6)

[0045] FIG. 5c illustrates the maximum value of the tilt angle (θ) that positions the optical axis (AX) between the -n-th order diffracted light beam and the -(n+1)-th order diffracted light beam and prevents the diffracted light beam from returning to the NA of the detection optical system (DL). The tilt angle (θ) is expressed as follows:

[0046] ...(7)

[0047] From equations (6) and (7), an inequality (8) describing a condition for preventing a diffracted light beam generated by the imaging plane (IS) from returning to the NA of the imaging optical system (DL) can be obtained:

[0048] ...(8)

[0049] Light from the light source (200) illuminates the diffracting optical element (171). The diffracted light beam generated by the diffracting optical element (171) passes through a lens (173), an aperture (174), two polarizing elements (185), a beam splitter (175), and a lens (176), and performs dipole illumination on the alignment mark (182) on the mold (M) and the alignment mark (183) on the substrate (W). The two polarizing elements (185) are positioned such that the polarization directions of the light beams emitted from each of the two poles and striking the substrate are orthogonal to each other. The aperture (174) is positioned within or near the pupil plane of the illumination optical system (IL). The two polarizing elements (185) are preferably positioned on the light source side with respect to the pupil plane.

[0050] Alignment marks (182, 183) are formed by diffraction gratings having different pitches in the measurement direction. The alignment marks (183) provided on the substrate (W) can be formed by a checkerboard grating pattern having a y-direction grating pitch and an x-direction grating pitch. A beam of diffracted light from the two alignment marks (182, 183) generates interference fringes (moiré fringes) that have periodicity in the x-direction as the measurement direction. Here, when the relative position between the mold (M) and the substrate (W) varies in the x-direction, the phase of the interference fringes changes according to the variation in the relative position. An image of the interference fringes is formed on the imaging plane (IS) of an imaging element (178) by an imaging optical system (DL) formed from a lens (176), a beam splitter (175), and a lens (177), and is detected (sensed) by the imaging element (178). An image detected by an imaging element (178) is transmitted to a control unit (180). Based on phase information within the image of the interference pattern, the control unit (180) calculates the relative position (amount of misalignment) between an alignment mark (182) on the mold (M) and an alignment mark (183) on the substrate (W). Based on the relative position, the control unit (180) performs alignment between the mold (M) and the substrate (W) by controlling a mold driving mechanism (132) and a stage driving mechanism that drives the substrate stage (162).

[0051] In this embodiment, the illumination optical system (IL) within the detection device (170) is configured to perform dipole illumination on the pupil plane of the illumination optical system (IL) by light containing two poles, and the polarization directions of the light beams emitted from each of the two poles and striking the substrate are orthogonal to each other. The polarization directions of the two light beams formed by the two polarization elements (185) are orthogonal to each other on the object to be detected. In this embodiment, the two polarization elements (185) are positioned on the light source side with respect to the pupil plane, but the positioning of the two polarization elements (185) is not limited thereto as long as the polarization directions are orthogonal to each other on the object to be detected. For example, the two polarization elements (185) may be positioned on the image plane side with respect to the aperture (174) configured to implement dipole illumination. Additionally, in this embodiment, the optical system illuminates a diffraction optical element, but it is not always necessary to use a diffraction optical element as long as 2-beam interference occurs in the optical system. Additionally, although a dipole illumination is used in this embodiment, it is not always necessary to use a dipole illumination, and the use of a unipolar illumination may also be considered. However, in this case, the defocus state may change due to changes in the device environment, such as changes in atmospheric pressure. If the defocus state changes, the image may shift due to asymmetric illumination and performance may be degraded.

[0052] A specific example of the inclination angle is described below. Here, it is assumed that the pitch (P) of the periodic structure of the microlens array of the imaging element (178) is 4.8 μm and the wavelength (λ) of the illumination light generated by the light source (200) is 760 nm. By substituting the values ​​of the pitch (P) and the wavelength (λ) and calculating Equation (4), the result shown in Table 1 can be obtained.

[0053] optical axis position Angle of inclination (θ) (degrees) Between the zero-order light beam and the first-order light beam 2.3 Between the primary light beam and the secondary light beam 6.9 Between the secondary light beam and the tertiary light beam 11.7

[0054] As exemplarily shown in Table 1, there are multiple options for the tilt angle (θ). The higher the order, the smaller the influence of the diffracted light beam. On the other hand, if the tilt angle (θ) is increased excessively, vignetting occurs. Considering this, it is preferable to set the tilt angle (θ) of the normal (N) of the imaging plane (IS) with respect to the optical axis (AX) to 6.9°. When the NA of the detection optical system (DL) is 0.009, θ according to Equation (5) det = 0.5°. Therefore, according to inequality (8), the inclination angle (θ) considering the NA of the detection optical system (DL) can be set to an angle greater than 4.8° and less than 9.0°. By doing so, in an arrangement where the optical axis (AX) is positioned between the first and second diffracted light from the imaging plane (IS), the first and second diffracted light can be prevented from returning to the detection optical system (DL).

[0055] FIG. 6 illustrates an exemplary arrangement of a detection device (170) according to a second embodiment. Matters not mentioned in the second embodiment may follow the first embodiment. In the second embodiment, detection in the x direction and detection in the y direction may be performed simultaneously. FIG. 6 illustrates a simplified arrangement of an illumination optical system (IL). Components corresponding to the lens (173), aperture (174), lens (176), and polarizing element (185) of FIG. 2a are not illustrated in FIG. 6.

[0056] The diffracting optical element (171) includes a first region (A') that forms an illumination light to illuminate a first part (A) of the object to be detected (184) and a second region (B') that forms an illumination light to illuminate a second part (B) of the object to be detected (184) that is different from the first part (A). The first region (A') of the diffracting optical element (171) diffracts light in the X direction within the surface of the diffracting optical element (171). The light diffracted in the X direction passes through a polarizing element (185) located within the pupil plane (187). The light beams with polarization directions in the X and Y directions pass through two poles arranged in the X direction and illuminate the first part (A) of the object to be detected (184). By evaluating the interference pattern of the first part (A) of the detection target (184), it is possible to detect the amount of misalignment in the relative position between the alignment mark on the mold (M) in the Y direction and the alignment mark on the substrate (W). Likewise, the second region (B') of the diffracting optical element (171) diffracts light in the Y direction from the surface of the diffracting optical element (171). The light diffracted in the Y direction passes through a polarizing element (186) located on the pupil plane (187). The light beams of polarization in the X and Y directions pass through two poles arranged in the Y direction and illuminate the second part (B) of the detection target (184). By evaluating the interference pattern of the second part (B) of the detection target (184), it is possible to detect the amount of misalignment in the relative position between the alignment mark on the mold (M) in the X direction and the alignment mark on the substrate (W).

[0057] As described above, according to the second embodiment, it is possible to simultaneously measure the positional misalignment in the X direction (first direction) and the positional misalignment in the Y direction (second direction intersecting the first direction).

[0058] In the first and second embodiments, the second periodic structure of the object to be detected is formed by a first pattern provided on the first object and a second pattern provided on the second object arranged to overlap with the first object. However, the second periodic structure of the object to be detected may be an alignment mark provided on an object (e.g., a substrate or a mold). In this case, the location of the alignment mark may be detected.

[0059] A method for manufacturing an article according to one embodiment is described below. The method for manufacturing an article according to this embodiment is suitable for manufacturing articles such as microdevices, for example, semiconductor devices, or devices having a microstructure. The method for manufacturing an article according to this embodiment includes the step of transferring a pattern of a plate onto a substrate using the aforementioned lithography device (e.g., an imprint device, an exposure device, a drawing device, etc.), and the step of obtaining an article by processing the substrate on which the pattern was transferred in the previous step. The method for manufacturing an article further includes other known steps (oxidation, film formation, deposition, doping, planarization, etching, resist removal, dicing, bonding, packaging, etc.). The method for manufacturing an article according to this embodiment is more advantageous than conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0060] The pattern of a cured product formed using an imprint device is used permanently on at least a portion of various types of articles or temporarily when manufacturing various types of articles. Articles include electrical circuit elements, optical elements, MEMS, printed elements, sensors, molds, etc. Electrical circuit elements include, for example, volatile or non-volatile semiconductor memory such as DRAM, SRAM, flash memory, or MRAM, or semiconductor elements such as LSI, CCD, image sensor, or FPGA. Molds include imprint molds, etc.

[0061] The pattern of the cured product is used directly as at least part of the constituent member of the aforementioned article or temporarily as a resist mask. After etching or ion implantation is performed in the substrate processing step, the resist mask is removed.

[0062] A method for manufacturing an article, in which an imprint device forms a pattern on a substrate, processes the substrate on which the pattern is formed, and manufactures an article from the processed substrate, will be described next. As shown in FIG. 7a, a substrate (1z), such as a silicon wafer, is prepared on which a workpiece (2z), such as an insulator, is formed on its surface. Subsequently, an imprint material (3z) is applied to the surface of the workpiece (2z) by an inkjet method or the like. Here, the state in which the imprint material (3z) is applied to the substrate as a plurality of droplets is shown.

[0063] As shown in FIG. 7b, the side of the imprint mold (4z) having a concave-convex pattern is oriented toward the imprint material (3z) on the substrate and faces it. As shown in FIG. 7c, the substrate (1z) coated with the imprint material (3z) comes 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 light as curing energy is irradiated onto the imprint material (3z) through the mold (4z), the imprint material (3z) is cured.

[0064] As illustrated in FIG. 7d, after the imprint material (3z) is cured, the mold (4z) is separated from the substrate (1z), and a pattern of the cured imprint material (3z) is formed on the substrate (1z). In the pattern of the cured material, the concave part of the mold corresponds to the convex part of the cured material, and the convex part of the mold corresponds to the concave part of the cured material. That is, the concave-convex pattern of the mold (4z) is transferred to the imprint material (3z).

[0065] As illustrated in FIG. 7e, when etching is performed using the pattern of the cured material as an etching resistance mask, the portion of the surface of the workpiece (2z) where the cured material is not present or remains thin is removed to form a groove (5z). As illustrated in FIG. 7f, when the pattern of the cured material is removed, an article having a groove (5z) formed on the surface of the workpiece (2z) can be obtained. Here, the pattern of the cured material is removed. However, instead of removing the pattern of the cured material after processing, this can be used as an interlayer dielectric film, i.e., a constituent member of an article, which is included in, for example, a semiconductor device.

[0066] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims shall be interpreted in the broadest manner to include all such modifications and equivalent structures and functions.

Claims

Claim 1 A detection device comprising: an imaging element having an imaging surface including a first periodic structure; and an optical system configured to illuminate a detection target having a second periodic structure different from the first periodic structure and to form an image of light from the detection target on the imaging surface, wherein light incident on the imaging surface generates a plurality of diffracted light beams of different orders according to the first periodic structure, and the normal of the imaging surface is tilted with respect to the optical axis such that the optical axis of the optical system is positioned between diffracted light beams of one or more adjacent orders among the plurality of diffracted light beams, and the optical system includes an imaging optical system configured to form an image of light from the detection target on the imaging surface, wherein the normal of the imaging surface is tilted with respect to the optical axis such that the diffracted light beams of one or more adjacent orders proceed toward the outside of the NA of the imaging optical system. Claim 2 delete Claim 3 In claim 1, the optical system includes an illumination optical system configured to illuminate the object to be detected, and the illumination optical system is a detection device that illuminates the object to be detected with illumination light comprising two poles. Claim 4 In paragraph 3, the illumination optical system comprises a detection device including an aperture diaphragm having two openings and a diffracting optical element configured to diffract light from a light source toward the two openings. Claim 5 In paragraph 4, the detection device further comprises two polarizing elements provided to correspond to each of the two apertures, wherein the illumination optical system is a detection device. Claim 6 In claim 5, the detection device wherein the two polarizing elements are arranged such that the polarization directions of the light beams from each polarizing element are orthogonal to each other. Claim 7 A detection device according to claim 1, wherein the first periodic structure comprises a first structure having periodicity in a first direction orthogonal to the normal, and a second structure having periodicity in a second direction orthogonal to the normal and the first direction, and light incident on the imaging surface generates a plurality of first diffracted light beams of different orders according to the first structure and generates a plurality of second diffracted light beams of different orders according to the second structure, and the normal of the imaging surface is tilted with respect to the optical axis of the optical system such that the optical axis is positioned between the first diffracted light beams of adjacent orders among the plurality of first diffracted light beams and between the second diffracted light beams of adjacent orders among the plurality of second diffracted light beams. Claim 8 A detection device according to claim 1, wherein the normal of the imaging plane is tilted with respect to the optical axis such that the bisector between the optical paths of adjacent order diffracted light beams overlaps with the optical axis of the optical system. Claim 9 A detection device according to claim 1, wherein the diffracted light beams of adjacent orders are a first-order diffracted light beam and a second-order diffracted light beam. Claim 10 A lithography device for transferring a pattern of a disc onto a substrate, comprising: a detection device specified in any one of claims 1 and 3 to 9 provided for alignment between the disc and the substrate; and a control unit configured to control alignment between the disc and the substrate based on the output of the detection device. Claim 11 A method for manufacturing an article, comprising: a step of transferring a pattern of a disc onto a substrate using a lithography device; and a step of obtaining an article from the substrate on which the pattern is transferred, wherein the lithography device comprises a detection device provided for alignment between the disc and the substrate and configured to transfer a pattern of a disc onto a substrate, and a control unit configured to control alignment between the disc and the substrate based on the output of the detection device, and wherein the detection device comprises an imaging element having an imaging surface including a first periodic structure; A method for manufacturing an article comprising an optical system configured to illuminate a detection target on a substrate having a second periodic structure different from a first periodic structure and to form an image of light from the detection target on the imaging surface, wherein the light incident on the imaging surface generates a plurality of diffracted light beams of different orders according to the first periodic structure, and the normal of the imaging surface is tilted with respect to the optical axis such that the optical axis of the optical system is positioned between diffracted light beams of one or more adjacent orders among the plurality of diffracted light beams, and the optical system includes an imaging optical system configured to form an image of light from the detection target on the imaging surface, wherein the normal of the imaging surface is tilted with respect to the optical axis such that the diffracted light beams of one or more adjacent orders proceed toward the outside of the NA of the imaging optical system. Claim 12 A detection system comprising a detection target including a detection device and a second periodic structure as defined in claim 1, wherein the second periodic structure of the detection target is formed by a first pattern provided to a first object and a second pattern provided to a second object arranged to overlap with the first object. Claim 13 In claim 12, the detection system generates a moiré pattern corresponding to the relative positions of the first pattern and the second pattern. Claim 14 In paragraph 12, the second periodic structure of the detection target is a detection system that is an alignment mark provided on the object. Claim 15 A detection device according to claim 1, wherein the optical system comprises an illumination optical system configured to illuminate a detection target and an imaging optical system configured to form an image of light from the detection target on the imaging surface, and the normal of the imaging surface is tilted with respect to the optical axis of the imaging optical system such that the optical axis of the imaging optical system is located between diffracted light beams of at least one order of adjacent order among the plurality of diffracted light beams.

Images