Detection apparatus, lithography apparatus, and article manufacturing method

Abstract

The present invention provides a detection device for detecting the position of a detection target including a diffraction grating pattern, wherein the detection device comprises: an illuminator configured to illuminate the detection target with illumination light including a plurality of wavelengths; a wavelength selector configured to select light of a specific wavelength from the diffraction light, the incident plane on which diffracted light from the detection target is incident; and a detector configured to receive light of a specific wavelength selected by the wavelength selector and detect the position of the detection target, wherein the positions on the incident plane on which light components of a plurality of wavelengths included in the illumination light are incident are different from each other, and the wavelength selector controls each of a plurality of elements according to the position on the incident plane.

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] To manufacture articles such as semiconductor devices, lithography devices such as projection exposure devices or imprint devices are used. In a projection exposure device, the shot area of ​​a substrate and a reticle are aligned with each other, and a pattern from the reticle is projected onto the shot area of ​​the substrate through a projection optical system, thereby forming a latent image pattern on the photoresist applied to the substrate. By developing the latent image pattern, a physical pattern is formed on the substrate. In an imprint device, an imprint material is placed on the shot area of ​​the substrate, and the imprint material is cured while in contact with the mold, thereby forming a pattern on the substrate consisting of the cured imprint material.

[0003] When aligning the shot area of ​​a substrate with the original plate, the relative position between the shot area and the original plate is detected. This detection can be performed by detecting the relative position between the mark provided on the shot area and the mark provided on the original plate. In a projection exposure device, for example, a box-in-box pattern can be formed by the mark on the substrate side and the mark on the original plate side. In an imprint device, for example, a moiré pattern can be formed by the mark on the substrate side and the mark on the original plate side. Japanese Patent Publication No. 2012-59853 describes evaluating the detection error derived from a mark detection system and optimizing lighting conditions (e.g., lighting method such as lighting numerical aperture or lighting wavelength) based on the evaluation result.

[0004] Here, if a detection target such as a mark has an asymmetric shape due to a manufacturing error (process error), an error may occur in the detection result of the position information of the mark. This error is called WIS (wafer-induced shift). Japanese Patent Publication No. 2019-4143 describes adjusting the intensity of each of the light components of multiple wavelengths in the illumination light so that the detection error of the detector is reduced, based on wavelength characteristics that represent the relationship between the wavelength of the light illuminating the detection target and the detection error of the detector, in order to reduce WIS. In Japanese Patent Publication No. 2019-4143, the intensity of each of the light components of multiple wavelengths included in the illumination light is adjusted by adjusting the output of each of the multiple light sources (semiconductor lasers) that emit light components of different wavelengths.

[0005] The detection error of the detector may vary depending on the position of the detection target, such as a mark, on the substrate. Therefore, it is desirable to change the wavelength of the light used to detect the position of the detection target so that the detection error is reduced depending on the position of the detection target on the substrate. However, as in the method described in Japanese Patent Publication No. 2019-4143, when adjusting the output of each of a plurality of light sources (semiconductor lasers), it takes a considerable amount of time for the output of each light source to stabilize, which is disadvantageous in terms of throughput (productivity). means of solving the problem

[0006] The present invention provides a technology advantageous for achieving both detection precision and throughput when, for example, detecting the location of a detection target.

[0007] According to one embodiment of the present invention, a detection device is provided for detecting the position of a detection target including a diffraction grating pattern, wherein the detection device comprises: an illuminator configured to illuminate a detection target with illumination light including a plurality of wavelengths; a wavelength selector configured to select light of a specific wavelength from the diffraction light, which includes an incident plane on which diffraction light from the detection target illuminated by the illuminator is incident; and a detector configured to receive light of a specific wavelength selected by the wavelength selector and detect the position of the detection target, wherein a plurality of elements are arranged in two dimensions on the incident plane of the wavelength selector to switch the induction / non-induction of light of the diffraction light to the detector, the diffraction directions of the light components of a plurality of wavelengths included in the illumination light on the detection target are different from each other, and the positions on the incident plane of the wavelength selector on which the light components are incident as diffraction light are different from each other, and the wavelength selector selects light of a specific wavelength from the diffraction light and induces the light to the detector by controlling each of the plurality of elements according to the position on the incident plane on which light of a specific wavelength is incident.

[0008] Further features of the present invention will be clearly understood by describing exemplary embodiments below with reference to the attached drawings. Brief explanation of the drawing

[0009] FIG. 1 is a drawing showing an example of the configuration of an imprint device; FIG. 2 is a diagram showing an example of the configuration of a position detector; FIG. 3 is a diagram showing an example of the configuration of a position detector; FIGS. 4a and 4b are drawings for explaining diffracted light; FIG. 5 is a diagram for explaining diffracted light; FIGS. 6a and 6b are drawings for explaining wavelength selection by a wavelength selector (liquid crystal filter); FIG. 7 is a diagram showing the relationship between the pupil intensity distribution of the illumination optical system and the numerical aperture NAo of the detection optical system; FIGS. 8a to 8d are drawings showing examples of configurations of a diffraction grating functioning as a mark; FIGS. 9a to 9d are drawings showing examples of configurations of a diffraction grating functioning as a mark; FIGS. 10a and FIGS. 10b are drawings for explaining the principle of detecting moiré patterns; FIGS. 11a and FIGS. 11b are drawings for explaining the principle of detecting moiré patterns; FIGS. 12a and FIGS. 12b are drawings for explaining the cross-sectional structure of a mark (detection target); FIGS. 13a and FIGS. 13b are diagrams illustrating the relationship between the wavelength of the illumination light and the detection error; FIG. 14 is a flowchart illustrating a method for determining a specific wavelength; FIG. 15 is a diagram showing the wavelength distribution (color distribution) of light incident on the incident surface of a liquid crystal filter; FIGS. 16a and FIGS. 16b are drawings illustrating wavelength selection by a wavelength selector (DMD); FIGS. 17a to 17f are drawings for explaining a method of manufacturing an article. Specific details for implementing the invention

[0010] Hereinafter, embodiments will be 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 numerous features are described in the embodiments, the invention is not limited to the invention requiring all of these features, and such numerous features may be appropriately combined. Furthermore, in the accompanying drawings, identical or similar components are assigned the same reference numerals, and redundant descriptions thereof are omitted.

[0011] In the following embodiments, an imprint device will be described exemplarily as a lithography device to which the detection device according to the present invention is applied, wherein the imprint device forms a pattern of an imprint material on a substrate using a mold that functions as a plate. However, the detection device according to the present invention may also be applied to other lithography devices, such as a projection exposure device that exposes a substrate by projecting a pattern of a reticle (mask) that functions as a plate onto the substrate through a projection optical system.

[0012] <1st Example>

[0013] A first embodiment according to the present invention will be described. FIG. 1 shows an example of the configuration of an imprint device (1) according to the present embodiment. The imprint device (1) is a device that forms a pattern of a cured product having a pattern with convex and concave portions of the mold (7) transferred by bringing an imprint material (9) supplied on a substrate (8) into contact with a mold (7) (pattern area (7a)) and applying curing energy to the imprint material (9). More specifically, the imprint device (1) places the imprint material (9) as a plurality of droplets on the substrate (8), and while the mold (7) (pattern area (7a)) having a pattern with convex and concave portions is in contact with the imprint material (9) on the substrate (8), the imprint material (9) is cured by light irradiation, etc. Afterward, when the imprint device (1) increases the gap between the mold (7) and the substrate (8) to separate the mold (7) from the cured imprint material (9), the pattern of the mold (7) is transferred to the imprint material (9) on the substrate, and a pattern consisting of the cured imprint material (9) can be formed on the substrate. This series of processes is called "imprint processing" and is performed for each of the multiple shot areas on the substrate.

[0014] The mold (7) is made of a material that transmits light (e.g., ultraviolet light) for curing the imprint material (9), such as quartz, and a pattern having convex and concave portions to be transferred to the imprint material (9) on the substrate (8) is formed in a portion of the surface on the substrate side (pattern area (7a)). The pattern area (7a) has a mesa shape, for example, with a step difference of about tens of micrometers. In addition, the material of the substrate (8) may be, for example, glass, ceramic, metal, semiconductor, resin, etc. If necessary, a member made of a material different from the material of the substrate may be provided on the surface of the substrate (8). In this embodiment, the substrate (8) is, for example, a silicon wafer, a compound semiconductor wafer, or quartz glass.

[0015] As an imprint material, a curable composition (also referred to as an uncured resin) that is cured by applying curing energy is used. Electromagnetic waves or heat may be used as the curing energy. The electromagnetic waves may be light selected from a wavelength range of, for example, 10 nm (including boundary values) to 1 mm (including boundary values), such as infrared, visible light, or ultraviolet light. The curable composition may be a composition that is cured by light irradiation or by heating. Among these, 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 a droplet or in the form of an island or film formed by connecting a plurality of droplets. The viscosity of the imprint material (viscosity at 25°C) may be, for example, 1 mPa·s (including boundary values) to 100 mPa·s (including boundary values).

[0016] In this specification and the accompanying drawings, directions will be indicated in an XYZ coordinate system in which directions parallel to the surface of the substrate (8) are defined as the XY plane. Directions parallel to the X-axis, Y-axis, and Z-axis of the XYZ coordinate system are the X direction, Y direction, and Z direction, respectively. Rotation around the X-axis, rotation around the Y-axis, and rotation around the Z-axis are θX, θY, and θZ, respectively. Control or driving with respect to the X-axis, Y-axis, and Z-axis means control or driving with respect to the direction parallel to the X-axis, the direction parallel to the Y-axis, and the direction parallel to the Z-axis, respectively. Additionally, control or driving with respect to the θX-axis, θY-axis, and θZ-axis means control or driving with respect to rotation around the axis parallel to the X-axis, rotation around the axis parallel to the Y-axis, and rotation around the axis parallel to the Z-axis, respectively. Additionally, position is information that can be determined based on coordinates of the X-axis, Y-axis, and Z-axis, and attitude is information that can be determined by values ​​of the X-axis, Y-axis, and Z-axis. Position determination means controlling the position and / or attitude. Alignment may include controlling the position and / or attitude of at least one of the substrate (8) and the mold (7).

[0017] [Configuration of the Imprint Device]

[0018] Hereinafter, the configuration of the imprint device (1) will be described by example. The imprint device (1) may include a curing unit (2), a position detector (3), a mold driving mechanism (4), a substrate driving mechanism (5), a dispenser (imprint material supply unit) (6), and a controller (15). The controller (15) is formed by a computer including a processor such as a CPU and memory, and controls the imprint processing by controlling the curing unit (2), the position detector (3), the mold driving mechanism (4), the substrate driving mechanism (5), and the dispenser (6). The controller (15) may be formed by, for example, a PLD (programmable logic device) such as an FPGA (field programmable gate array), an ASIC (application specific integrated circuit), a general-purpose computer with a built-in program, or a combination of some or all of these.

[0019] After a contact step in which the imprint material (9) on the substrate (8) is brought into contact with the mold (7), the curing unit (2) cures the imprint material (9) by irradiating the imprint material (9) with curing energy. The curing unit (2) may include, for example, a light source that generates light for curing the imprint material (9). The light source may be, for example, a high-pressure mercury lamp, various excimer lamps, an excimer laser, or a light-emitting diode. As described above, the mold (7) includes a pattern area (7a), and a pattern is formed in the pattern area (7a) by a concave portion. When the imprint material (9) on the substrate (8) and the pattern area (7a) of the mold (7) are in contact, the concave portion of the pattern area (7a) can be filled with the imprint material (9).

[0020] The substrate driving mechanism (5) may be configured to hold and support the substrate (8) and to drive the substrate (8) along a plurality of axes (e.g., three axes of the X-axis, Y-axis, and θZ-axis, preferably six axes of the X-axis, Y-axis, Z-axis, θX-axis, θY-axis, and θZ-axis). The mold driving mechanism (4) may be configured to hold and support the mold (7) and to drive the mold (7) along a plurality of axes (e.g., three axes of the Z-axis, θX-axis, and θY-axis, preferably six axes of the X-axis, Y-axis, Z-axis, θX-axis, θY-axis, and θZ-axis). The substrate driving mechanism (5) and the mold driving mechanism (4) form a driving mechanism that drives at least one of the substrate (8) and the mold (7) so that the relative position between the substrate (8) and the mold (7) is adjusted. Relative position adjustment by a driving mechanism includes driving to contact the mold (7) with the imprint material (9) on the substrate (8) and to separate the mold (7) from the cured imprint material (9) (pattern of the cured material).

[0021] To detect the relative position between the shot area of ​​the mold (7) and the substrate (8), the position detector (3) (detection device) detects the relative position between the mark (11) (second mark) provided in the shot area and the mark (10) (first mark) provided in the mold (7) as position information. Here, the mark (11) and the mark (10) each form a target for position information detection. The mark (11) and the mark (10) may each be, for example, a mark forming a moiré pattern. In this case, based on the moiré pattern, the relative position between the mark (11) and the mark (10) may be detected by the position detector (3) as position information of the detection target. Alternatively, the mark (11) and the mark (10) may form a box-in-box mark. In this case, the position of the mark (11) and the position of the mark (10) may be detected by the position detector (3) as position information of the detection target.

[0022] The position detector (3) includes an optical system configured to observe a mark, and the optical axis of the optical system may be positioned perpendicular to the surface of the substrate (8). The position detector (3) may be driven by a driving mechanism configured to position the position detector (3) in the X and Y directions according to the position of the mark of the detection target. Additionally, the position detector (3) may be driven in the Z direction for focus adjustment, or may include an optical system for focus adjustment.

[0023] Based on position information detected by the position detector (3), the controller (15) controls at least one of the substrate driving mechanism (5) and the mold driving mechanism (4) so ​​that the shot area of ​​the mold (7) and the substrate (8) are aligned. The imprint device (1) may include a deformation mechanism that deforms the mold (7) to match the shape of the shot area of ​​the substrate (8) with the shape of the pattern area (7a) of the mold (7). In this case, the controller (15) may detect the shape difference between the shot area and the pattern area (7a) based on the position information detected by the position detector (3), and control the deformation mechanism based on the shape difference.

[0024] The dispenser (6) places imprint material (9) as a plurality of droplets on the shot area of ​​the substrate (8). The dispenser (6) may be configured to discharge imprint material (9) as a plurality of droplets at a timing according to a drop recipe while the substrate (8) is driven by the substrate driving mechanism (5). The drop recipe is information (map) indicating the placement of a plurality of droplets of imprint material (9) on the shot area. The dispenser (6) may be provided outside the imprint device (1). In this case, the substrate (8) may be provided to the imprint device (1) with the imprint material (9) placed on the substrate (8) by the dispenser (6).

[0025] [Imprint Processing]

[0026] Hereinafter, an imprint processing by the imprint device (1) will be described. First, the substrate (8) is transported by a substrate transport mechanism (not shown) to a substrate holder (not shown) of a substrate driving mechanism (5) and is held and supported by the substrate holder. Next, under the control of a controller (15), the substrate (8) is driven by the substrate driving mechanism (5) so that a shot area (hereinafter simply referred to as "shot area") of the pattern formation target (imprint target) is placed below the dispenser (6). While the substrate (8) is driven by the substrate driving mechanism (5), an imprint material (9) is placed on the shot area by the dispenser (6).

[0027] Next, under the control of the controller (15), the substrate (8) is driven by the substrate driving mechanism (5) so that the shot area is positioned below the mold (7). Next, under the control of the controller (15), at least one of the mold driving mechanism (4) and the substrate driving mechanism (5) is operated so that the imprint material (9) on the shot area and the pattern area (7a) of the mold (7) come into contact.

[0028] Next, under the control of the controller (15), position information (relative position) between the shot area of ​​the substrate (8) and the pattern area (7a) of the mold (7) is detected by the position detector (3), and alignment between the shot area and the pattern area (7a) is performed based on the position information. Alignment between the shot area and the pattern area (7a) can be performed by at least one of the substrate driving mechanism (5) and the mold driving mechanism (4). At this time, the mold (7) can be deformed by a deformation mechanism based on the shape difference between the shot area and the pattern area (7a).

[0029] Next, under the control of the controller (15), the curing unit (2) irradiates the imprint material (9) with curing energy through the mold (7) and cures the imprint material (9). Next, under the control of the controller (15), at least one of the mold driving mechanism (4) and the substrate driving mechanism (5) is operated so that the cured material of the imprint material (9) on the shot area and the pattern area (7a) of the mold (7) are separated. Accordingly, a pattern consisting of the cured material of the imprint material (9) is formed on the shot area.

[0030] [Example of detector configuration]

[0031] Hereinafter, the configuration of the position detector (3) (detection device) will be described by example. FIG. 2 shows an example of the configuration of the position detector (3). The position detector (3) may include an illumination optical system (31), a detection optical system (32), and a detector (33). In this embodiment, the illumination optical system (31) and the detection optical system (32) may be configured to share some components.

[0032] The illumination optical system (31) includes a light source unit (31a) configured to emit illumination light including multiple wavelengths (wavelength bands), and is an illuminator that illuminates a detection target with illumination light from the light source unit (31a). The illumination optical system (31) according to the present embodiment guides the illumination light from the light source unit (31a) onto the same optical axis as the detection optical system (32) by means of an optical device such as a prism (34), and illuminates the detection target mark (10) and mark (11) obliquely. The light source unit (31a) may be formed by a single light source that emits illumination light including multiple wavelengths, or may be formed by multiple light sources that emit light components of different wavelengths. As a light source included in the light source unit (31a), at least one of a super continuum light source, a halogen lamp, an LED, a semiconductor laser (LD), a plasma light source, a high-pressure mercury lamp, and a metal halide lamp may be used. As an illumination light, light having a wavelength that does not cure the imprint material (9) may be used. In addition, the mark (10) and the mark (11) to be detected may each be formed by a diffraction grating (i.e., may include a diffraction grating pattern).

[0033] The detection optical system (32) induces at least a portion of the diffracted light on the detection target (mark (10) and mark (11)) illuminated by the illumination optical system (31) (illuminator) to the detector (33). The detector (33) receives at least a portion of the diffracted light induced by the detection optical system (32) and detects the position of the detection target. In this embodiment, the detector (33) may include an imaging device such as a CCD or CMOS image sensor. The detection optical system (32) forms a moiré pattern (interference pattern) on the imaging surface of the imaging device (detector (33)) by the interference of the diffracted light from the mark (10) and mark (11) illuminated by the illumination optical system (31). Since the moiré pattern is formed by diffracted light from the mark (10) of the mold (7) and diffracted light from the mark (11) of the substrate (8), the amount of light in the moiré pattern may depend on the diffraction efficiency of the mold (7) and the substrate (8). In particular, since the diffraction efficiency varies depending on the wavelength, there exist wavelengths where the moiré pattern can be detected efficiently and wavelengths where it is difficult to detect the moiré pattern. Light at wavelengths where it is difficult to detect the moiré pattern may be noise.

[0034] Here, the detector (33) can be understood to have a processing unit (processor) that acquires the position of the detection target (i.e., the relative position between the mark (10) and the mark (11)) based on an image of the moiré pattern captured by an imaging device. The processing unit can be understood to form part of the controller (15). Additionally, when measuring the position of the mold (7) and the position of the substrate (8) individually, the position detector (3) may be configured to detect only the mark (11) of the substrate (8), as shown in FIG. 3, or may be configured to detect only the mark (10) of the mold (7). For example, when the position of the mark (11) of the substrate (8) is detected by the position detector (3), the position of the substrate (8) can be measured.

[0035] A prism (34) may be placed on or near the pupil plane common to the illumination optical system (31) and the detection optical system (32). The prism (34) includes a bonding surface, and the bonding surface may be provided with a reflective film (34a) configured to reflect light from the periphery of the pupil plane of the illumination optical system (31). The reflective film (34a) also functions as an aperture diaphragm that defines the size of the pupil (or detection NA: NAo) of the detection optical system (32). The prism (34) may be a half-prism having a translucent film on the bonding surface. Instead of a prism, a plate-shaped optical device with a reflective film formed on its surface may be used. Alternatively, a transparent portion may be formed on the periphery of the prism (34) in FIG. 2, a reflective portion may be formed in the center, and the position of the light source unit (31a) and the position of the detector (33) (imaging device) may be interchanged.

[0036] The illumination optical system (31) and the detection optical system (32) include individual aperture apertures (35, 36) on the pupil plane. The position of the aperture aperture (36) of the detection optical system (32) (detection side) has a conjugate relationship with the position of the aperture aperture (35) of the illumination optical system (31) (illumination side). Additionally, at the position of the aperture aperture (36) of the detection optical system (32), a wavelength selector (80) is provided to select light of a specific wavelength from the diffracted light and induce it to the detector (33) (imaging device). The wavelength selector (80) includes an incident plane (80a) into which diffracted light from the detection target (mark (10) and mark (11)) illuminated by the illumination optical system (31) is incident. On the incident plane (80a), a plurality of elements are arranged in two dimensions to switch the induction / non-induction of the diffracted light to the detector (33). As described above, the diffracted light from a detection target illuminated by illumination light containing multiple wavelengths includes light of a wavelength that can efficiently detect moiré patterns and light of a wavelength that is difficult to detect moiré patterns (i.e., light that may be noise). The wavelength selector (80) is configured to select light of a specific wavelength that can efficiently detect moiré patterns from the diffracted light and guide it to the detector (33). In this embodiment (the example shown in FIG. 2), an example will be described in which an optical device is used as the wavelength selector (80), in which a plurality of elements (pixels) for switching the transmission / non-transmission of diffracted light are arranged two-dimensionally on the incident plane (80a). A liquid crystal filter (81) may be used as the optical device.

[0037] FIGS. 4a, FIGS. 4b, and FIGS. 5 are drawings for explaining diffracted light generated when the mark (10) of the mold (7) and the mark (11) of the substrate (8) are illuminated. When the diffraction grating patterns of the mark (10) and the mark (11) are illuminated by illumination light containing multiple wavelengths (wavelength bands), diffracted light is generated by the mark (10) and the mark (11). FIG. 4a shows the light diffracted in the first order. Since the diffraction directions (diffraction angles) of the light components of multiple wavelengths included in the illumination light differ from one another depending on the wavelengths, the wavelengths can be divided. More specifically, the longer the wavelength, the larger the angle of the diffracted light. As shown in FIG. 4a, red light is reflected (diffracted) at a larger angle than violet light for zero-order reflected light. Accordingly, as shown in FIG. 5, when a detection target (mark (10) and mark (11)) is obliquely illuminated with illumination light containing multiple wavelengths, light components of multiple wavelengths included in the illumination light are incident on the incident surface (80a) of the wavelength selector (80) at different locations as diffracted light. As a result, the wavelength selector (80) selects light of a specific wavelength from the diffracted light and directs it to the detector (33) by controlling each of the multiple elements according to the location where light of a specific wavelength is incident on the incident surface (80a). The lens (37) is placed on the optical path between the wavelength selector (80) and the detection target and can be configured to cause light components of multiple wavelengths diffracted by the detection target to be incident on the incident surface (80a) of the wavelength selector (80) at different locations. Note that oblique illumination of the detection target means performing illumination such that the illumination light is incident on the detection target at an oblique angle. Light of a specific wavelength is, for example, light of a wavelength capable of efficiently detecting moiré patterns as described above.

[0038] The incident position of light of each wavelength on the incident surface (80a) of the wavelength selector (80) is determined by the configuration of the position detector (3). Accordingly, information indicating the relationship between each of the plurality of wavelengths included in the illumination light and the incident position of the light on the incident surface (80a) (hereinafter referred to as first information) can be obtained in advance through simulation or experiment. Accordingly, based on the first information, the wavelength selector (80) can control each of the plurality of elements to select light of a specific wavelength from the diffracted light and guide it to the detector (33).

[0039] Here, as shown in FIG. 4b, even when the detection target is only the mark (11) of the substrate (8), the wavelength of the first-order diffracted light from the mark (11) can be divided by selecting the pitch of the diffraction grating pattern of the mark (11). Also, even when the detection target is only the mark (10) of the mold (7), the wavelength of the first-order diffracted light from the mark (10) can be divided by selecting the pitch of the diffraction grating pattern of the mark (10). In this embodiment, the first-order diffracted light has been described. This also applies when second-order, third-order, or higher-order diffracted light is used.

[0040] Next, with reference to FIG. 2, an example configuration for detecting by illuminating a detection target obliquely will be described. FIG. 2 shows an example of illuminating a detection target (mark (10) and mark (11)) obliquely using an aperture diaphragm (35). The marks (10) and mark (11) in FIG. 2 are marks used to measure the relative position in the Y direction between the mold (7) and the substrate (8). When the marks (10) and mark (11) are illuminated from a non-measurement direction (X direction), a moiré pattern in the Y direction can be detected. The first-order diffracted light of the illumination light, which is wavelength-divided by the detection target, is incident on a liquid crystal filter (81) (incident surface (80a)) which functions as a wavelength selector (80), as shown in FIG. 2.

[0041] As described above, the liquid crystal filter (81) is formed by a plurality of elements (pixels), and at each pixel, whether to transmit a light beam (diffracted light) can be selected. As the liquid crystal filter (81), for example, a liquid crystal device including 640x480 pixels can be used. Under the control of the controller (15), the wavelength selector (80) (liquid crystal filter (81)) selects whether to transmit incident light for each pixel and guide it to the detector (33). That is, as shown in FIGS. 6a and 6b, depending on the position where light of a specific wavelength is incident on the incident surface (80a), the wavelength selector (80) (liquid crystal filter (81)) controls (switches) the transmission / non-transmission of each pixel so that light of a specific wavelength is transmitted. Accordingly, light of a specific wavelength can be selected from the first-order diffracted light and guided to the detector (33).

[0042] FIG. 7 illustrates the relationship between the pupil intensity distribution (IL1 and IL2) of the illumination optical system (31) of the position detector (3) and the numerical aperture NAo of the detection optical system (32). The pupil intensity distribution of the illumination optical system (31) may include a first pole IL1 and a second pole IL2. When the relative position between the mold (7) and the substrate (8) is measured by the moiré pattern detection method, the first pole IL1 is the illumination for the X mark and the second pole IL2 is the illumination for the Y mark. When measuring only a diffraction grating pattern having a line-and-space pattern rather than a moiré pattern, the diffracted light from the diffraction grating pattern having a line-and-space pattern is diffracted in the direction of measurement. Therefore, the first pole IL1 is the illumination for the Y mark and the second pole IL2 is the illumination for the X mark.

[0043] The first pole IL1 and the second pole IL2 shown in FIG. 7 are positioned on the positive side in the Y direction and the positive side in the X direction, respectively. However, both may be positioned on the negative side. Cases where only the first pole IL1 or the second pole IL2 is used may also be considered. The aperture diaphragm (35) is formed by forming a Cr film on a metal plate or glass and is positioned on the pupil surface of the illumination optical system (31). By doing so, a plurality of poles (i.e., the first pole IL1 and the second pole IL2) are formed by light beams from the light source unit (31a), and a light beam (light flux) for obliquely illuminating the detection target can be generated. That is, among the light beams from the light source unit (31a), light beams that are not used for measurement (i.e., light beams that may be noise) can be blocked. Additionally, when the number of apertures of the aperture diaphragm (35) is changed, a single pole, a bipolar, or a quadruple pole can be formed. In this embodiment, to avoid interference of light wavelength-divided by the marks (10) and (11), it is preferable to form a single pole in each of the X and Y directions, such as the first pole IL1 and the second pole IL2, as shown in FIG. 7. A light beam from the illumination optical system (31) passes through the aperture diaphragm (35) and is reflected by the reflective film (34a) of the prism (34) to obliquely illuminate the marks (10 and 11).

[0044] [Detection of Moiré Patterns]

[0045] The principle of generating moiré patterns by diffracted light from the mark (10) and the mark (11), and the detection of the relative position between the mark (10) (mold (7)) and the mark (11) (shot area on the substrate (8)) using the moiré pattern will be described later with reference to FIGS. 8a and 8b. The diffraction grating (41) shown in FIG. 8a can be provided as the mark (10) on the mold (7), and the diffraction grating (42) shown in FIG. 8b can be provided as the mark (11) on the substrate (8). The diffraction grating (41) and the diffraction grating (42) are marks used to detect the relative position in the X direction between the mark (10) (mold (7)) and the mark (11) (substrate (8)), and the period of the patterns (grids) in the X direction, which is the detection direction, is slightly different. When two diffraction gratings (41 and 42) with different grating periods are superimposed, a moiré pattern appears, which is a pattern with a period that reflects the difference in period between the diffraction gratings, due to the interference of diffracted light from the two diffraction gratings. Since the phase of the moiré pattern changes depending on the relative position between the diffraction gratings, the relative position between the mark (10) and the mark (11), that is, the relative position between the mold (7) and the substrate (8) (shot area), can be obtained by detecting the moiré pattern.

[0046] More specifically, when a diffraction grating (41) and a diffraction grating (42) with slightly different periods are superimposed, the diffracted light components from the diffraction gratings (41 and 42) are superimposed, and a moiré pattern having a period that reflects the difference in period is generated, as shown in FIG. 8c. The light / dark position (phase) of the moiré pattern changes according to the relative position between the diffraction grating (41) and the diffraction grating (42). For example, if one of the diffraction gratings (41 and 42) is shifted in the X direction, the moiré pattern shown in FIG. 8c can change as shown in FIG. 8d. The moiré pattern is generated as a pattern of a large period that increases the amount of positional deviation between the diffraction grating (41) and the diffraction grating (42). As a result, the relative position between the diffraction grating (41) and the diffraction grating (42) can be accurately detected even if the resolution of the detection optical system (32) (detector (33)) is low. Here, in order to accurately detect moiré patterns, it is preferable that the system has a dark field configuration in which diffraction gratings (41 and 42) are illuminated by oblique incidence (i.e., obliquely illuminated), diffracted light diffracted in a vertical direction by diffraction gratings (41 and 42) is detected by a detector (33), and zero-order light is not detected.

[0047] Light diffracted in the X direction by diffraction gratings with slightly different periods is incident on a detection area (NAo) on the pupil of a detection optical system (32) while maintaining relative position information in the X direction, and is detected by a detector (33) (imaging device). Using this, the relative position between two diffraction gratings can be obtained. Additionally, the detector (33) (imaging device) can form an image from the received light and obtain the relative position between the origin position of the image and the deviation of the mark.

[0048] Additionally, one of the diffraction gratings (41 and 42) may be a diffraction grating having a checkerboard pattern as shown in FIG. 9a, and the other diffraction grating may be a diffraction grating as shown in FIG. 9b. The diffraction grating shown in FIG. 9a includes a pattern periodically arranged in the detection direction and a pattern periodically arranged in a direction orthogonal to the detection direction. In the configuration shown in FIG. 9a and 9b, light from the first pole IL1 is incident on the diffraction gratings and is diffracted in the Y direction and simultaneously diffracted in the X direction by the diffraction grating of the checkerboard pattern. Note that FIG. 9a and 9b show marks (diffraction gratings) where the detection direction is the X direction. Marks (diffraction gratings) where the detection direction is the Y direction may be configured in the same way. FIG. 9c and 9d show marks (diffraction gratings) where the detection direction is the Y direction. A diffraction grating having a checkerboard pattern shown in FIG. 9a or 9c is provided on one of the mold (7) and the substrate (8), and a diffraction grating having a line-and-space pattern shown in FIG. 9b or 9d is provided on the other of the mold (7) and the substrate (8).

[0049] Here, light from the second pole IL2 in the pupil intensity distribution shown in FIG. 7 is not used to detect the relative positions between the diffraction gratings shown in FIG. 9a and FIG. 9b. However, when detecting the relative positions between the diffraction gratings shown in FIG. 9c and FIG. 9d, light from the second pole IL2 is used to detect the relative positions between the diffraction gratings, and light from the first pole IL1 is not used to detect the relative positions between the diffraction gratings. Additionally, when the set of diffraction gratings shown in FIG. 9a and FIG. 9b and the set of diffraction gratings shown in FIG. 9c and FIG. 9d are placed in the same field of view of the detection optical system (32) (detector (33)), and the relative positions in two directions are detected simultaneously, the pupil intensity distribution shown in FIG. 7 is advantageous.

[0050] Next, the principle of detecting a moiré pattern by a detector (33) in a superimposed state of two marks, namely mark (10) (a diffraction grating with a checkerboard pattern) and mark (11) (a diffraction grating with a line-and-space pattern), will be explained with reference to FIGS. 10a and 10b and FIGS. 11a and 11b.

[0051] FIG. 10a illustrates the pitch of a mark having a checkerboard pattern, and FIG. 10b illustrates the pitch of a diffraction grating having a line-and-space pattern. The mark having a checkerboard pattern shown in FIG. 10a has a pitch Pmm in the X direction and a pitch Pmn in the Y direction. The mark having a line-and-space pattern shown in FIG. 10b has a pitch Pw in the X direction. Note that the periods of the mark (10) in the X direction and the Y direction may be the same, or the periods of the mark (10) in the X direction and the Y direction may be different.

[0052] FIG. 11a is a view of the mark (10) and mark (11) with the detection direction in the X direction as seen from the X direction, and FIG. 11b is a view of the mark (10) and mark (11) as seen from the Y direction. The moiré pattern used to detect the relative position with respect to the X direction is generated by light from the first pole IL1 positioned on the Y-axis on the illumination pupil plane shown in FIG. 7. Here, if the wavelength of the light is denoted as λ and the diffraction order as n, the diffraction angles φmn, φmm, and φw by the diffraction gratings are expressed as follows.

[0053] sinφmn=nλ / Pmm ...(1)

[0054] Therefore, if the diffraction angles by the mark (10) and the mark (11) are φm and φw, respectively, then mathematical equations (2) and (3) are obtained.

[0055] sinφmm=nλ / Pm ...(2)

[0056] sinφw=nλ / Pw ...(3)

[0057] FIGS. 11a and FIGS. 11b illustrate the case where n=1. FIGS. 11a is a drawing showing the YZ plane. FIGS. 11a illustrates incident light from the first pole IL1 (hereinafter referred to as incident light IL1), specularly reflected light D0 of the incident light IL1, and diffracted light D1 from a mark (10) including a diffraction grating having a checkerboard pattern. Diffracted light D1 is not a light beam reflected (diffracted) by the mark (10) of the mold (7), but a light beam reflected (diffracted) by the mark (11) of the substrate (8). Diffracted light D1 is detected by a detector (33).

[0058] Here, as shown in mathematical formula (1), the emission angle of the diffracted light changes according to the wavelength. The light divided for each wavelength is Fourier transformed using a lens (37), etc., and is incident on the Fourier transform plane at a different position for each wavelength. That is, information on the emission angle of the diffracted light can be converted into position information on the Fourier transform plane. In this embodiment, the wavelength selector (80) (liquid crystal filter (81)) is placed on the Fourier transform plane. Accordingly, as described above with reference to FIG. 5, multiple light components of wavelengths included in the diffracted light are incident on the incident plane (80a) of the wavelength selector (80) at different positions, and only light of a specific wavelength can be selected from the diffracted light by the wavelength selector (80).

[0059] FIG. 11b is a diagram showing the XZ plane and represents the light beam of the first-order diffracted light of the incident light IL1. Diffracted light components D2 and D2' represent ±1st-order light components diffracted by the mark (10), respectively, and diffracted light components D4 and D4' represent ±1st-order light components diffracted only by the mark (11), respectively. Diffracted light components D3 and D3' represent light diffracted once by the mark (10) and light diffracted once by the mark (11), respectively, and correspond to diffracted light D1 of FIG. 11a. The pitch of the mark (10) and the mark (11) in the X direction (detection direction) is slightly different. As a result, as indicated by φ△ in FIG. 11b, the angle in the XY plane between the diffracted light D3 generated by the +1st order light on the mark (10) and the -1st order light on the mark (11), and the diffracted light D3' generated by the -1st order light on the mark (10) and the +1st order light on the mark (11) is slightly different. Due to this slight difference in angle (φ△), a beat signal (moiré pattern) is generated. For example, if the pitches of the diffraction grating patterns are expressed as Pmn=4㎛, Pm=1㎛, and Pw=1.04㎛, the period of the moiré pattern becomes PmxPw / (Pw-Pm) / 2=13㎛. Note that the pitches of the diffraction grating patterns are not limited to the values ​​described above and can be determined by considering the size of each mark.

[0060] [Detection error in the detector]

[0061] Next, the detection error of the position detector (3) (detector (33)) will be explained. FIGS. 12a and FIGS. 12b are drawings to exemplarily explain the cross-sectional structure of a mark (target of detection). In the example shown in FIGS. 12a and FIGS. 12b, the mark has a structure formed of three layers. Since these layers have steps, diffraction of light occurs due to the steps when light is irradiated. Thus, the structure can be recognized as a mark. The mark (11c) shown in FIG. 12a is a mark without shape error (manufacturing error). The mark (11d) shown in FIG. 12b is a mark with asymmetric shape error (manufacturing error). Since the mark (11c) has a symmetric structure, the diffracted light has an ideal diffraction angle. As a result, no error occurs in the position of the detected mark. On the other hand, since the mark (11d) has an asymmetric shape error, the diffraction angle of the diffracted light deviates from the ideal state by an amount corresponding to the asymmetry. Therefore, the detected position of the mark may have an error relative to the actual position. That is, in the position detector (3) (detector (33)), a detection error in the position of the mark may occur. If the error is large, the overlap precision between the layers of the substrate is reduced, and manufacturing defects may occur.

[0062] Referring to FIGS. 13a and 13b, the relationship between the wavelength of the illumination light of the position detector (3) and the detection error of the position detector (3) is explained exemplarily. Here, the detection error of the position detector (3) is a detection error that occurs because the mark (11) has an asymmetric shape (manufacturing error). FIG. 13a shows the cross-sectional shapes of the mark (11) of the substrate (8) and the mark (10) of the mold (7) when the mold (7) (pattern area (7a)) and the substrate (8) (shot area) are brought into contact through the imprint material (9). FIG. 13b shows the result of a simulation performed on the cross-sectional shapes shown in FIG. 13a (wavelength characteristics (second information) indicating the relationship between each of the plurality of wavelengths included in the illumination light of the position detector (3) and the detection error of the position detector (3).

[0063] In the simulation, the mark (11) is formed by a diffraction grating pattern having a checkerboard pattern, the step (52) of the diffraction grating pattern is 200 nm, the pitch (51) is 1,000 nm, and the shape error (53) is 40 nm. The base material of the substrate (8) is formed by a silicon substrate, and the mark (11) is made of SiO2. A mold (7) is placed on the mark (11) with an imprint material (9) interposed therein.

[0064] FIG. 13b shows the simulation results (wavelength characteristics). The horizontal axis of FIG. 13b represents the wavelength of light used to detect the mark, and the vertical axis represents the detection error. The detection error indicated along the vertical axis is the detection error of the position detector (3) caused by the asymmetric shape of the mark (11) (detection error of the relative position between the mark (10) and the mark (11). As shown in FIG. 13b, the detection error of the position detector (3) changes depending on the wavelength of the light, and the mark cannot be detected in the wavelength range of 590 to 600 nm. For this reason, this wavelength band should not be used. In addition, wavelengths 540 nm and 650 nm are wavelengths where the detection error is reduced, and even if the mark shape contains a small error, the mark can be stably detected near the wavelength. That is, the detection error of the position detector (3) can be reduced. Therefore, it is desirable to detect the mark by actively using light of this wavelength (around 540 nm or 650 nm) as light of the specific wavelength described above.

[0065] [Method for Determining Specific Wavelength]

[0066] Hereinafter, with reference to FIG. 14, a method for determining a specific wavelength to be selected by the wavelength selector (80) (liquid crystal filter (81)) of the position detector (3) will be described by example. FIG. 14 is a flowchart illustrating a method for determining a specific wavelength. Each step in the flowchart of FIG. 14 can be controlled by a controller (15). In FIG. 14, steps S101 to S103 are steps for forming a test sample. Step S104 is a step of obtaining wavelength characteristics regarding the test sample by detecting the relative position between the mark (10) and the mark (11) by the position detector (3) while changing the wavelength to be detected using the test sample. The wavelength characteristics are information (second information) representing the relationship between each of the plurality of wavelengths included in the illumination light and the detection error of the position detector (3) (detector (33)). Step S105 is a step of determining a specific wavelength to be selected by the wavelength selector (80) and induced in the detector (33) based on the wavelength characteristics obtained in step S104. Step S106 is a step of storing information on a specific wavelength determined in Step S105. Steps S101 to S106 will be described in detail below.

[0067] In step S101, a substrate (8) having the same structure as a substrate for manufacturing an article is returned to a substrate holding support of a substrate driving mechanism (5) and is held and supported by the substrate holding support. Also in step S101, a mold (7) for manufacturing an article is returned to a mold holding support of a mold driving mechanism (4) and is held and supported by the mold holding support. In step S102, a shot area as a target for forming a test sample on the substrate (8) and a pattern area (7a) of the mold (7) are pre-aligned. Pre-alignment can be performed, for example, by detecting the relative position between one or more marks (11) of a shot area of ​​the substrate (8) and a mark (10) of the mold (7) by a position detector (3) while the substrate (8) and the mold (7) are separated.

[0068] In step S103, an imprint material (9) is placed on a shot area on a substrate (8) as a target for forming a test sample by means of a dispenser (6). Next, in step S103, at least one of a mold driving mechanism (4) and a substrate driving mechanism (5) is driven so that the imprint material (9) and the pattern area (7a) of the mold (7) come into contact with each other. Next, in step S103, the shot area and the pattern area (7a) of the mold (7) are aligned by means of a position detector (3) while detecting the relative position between the mark (11) on the shot area as a target for forming a test sample and the mark (10) of the mold (7). Here, the detection result by the position detector (3) may include a detection error caused by the asymmetric shape of the mark (11) on the substrate (8). Next, in step S103, the imprint material (9) is cured by a curing unit (2). Accordingly, a structure having a pattern formed from the cured material of the imprint material (9) is formed in the shot area as a test sample.

[0069] The wavelength used for pre-alignment in step S102 may be the same as or different from the wavelength used for alignment during imprinting in step S103. Since an air layer is formed between the substrate (8) and the mold (7) during pre-alignment, the optimal wavelength for detection may be different from that during imprinting. In this case, alignment can be performed accurately by changing the wavelength conditions between pre-alignment and imprinting.

[0070] In step S104, while the pattern formed by the cured material of the imprint material (9) is in contact with the pattern area (7a) of the mold (7), the wavelength characteristics of the test sample formed in step S103 are acquired using a position detector (3). More specifically, the wavelength selector (80) (controller (15)) performs wavelength selection by controlling each of the plurality of elements arranged on the incident surface (80a) so that each of the light components of a plurality of wavelengths (wavelength bands) included in the illumination light from the light source unit (31a) is received (detected) as test light by the detector (33). After that, the detector (33) detects the position of the test sample for each of the light components of the plurality of wavelengths. For example, among the plurality of wavelengths included in the illumination light, the light of the first wavelength is selected by the wavelength selector (80) and guided to the detector (33), and the detector (33) detects the position of the test sample. Next, among the multiple wavelengths included in the illumination light, a second wavelength light different from the first wavelength is selected by the wavelength selector (80) and guided to the detector (33), and the position of the test sample is detected by the detector (33). In this way, while changing the wavelength of the light selected by the wavelength selector (80) and guided to the detector (33), the detector (33) detects the position of the test sample for each wavelength. Thus, wavelength characteristics as shown in FIG. 13b can be obtained. It is preferable that such wavelength characteristics be obtained for each of the multiple positions on the substrate (e.g., each of the multiple shot regions on the substrate). In this case, it is preferable that the wavelength selector changes a specific wavelength between the multiple shot regions (between the multiple regions) based on the wavelength characteristics obtained for each of the multiple shot regions. Note that in this embodiment, a test sample is formed in steps S101 to S103, and wavelength characteristics are obtained using the test sample in step S104. Wavelength characteristics as shown in Fig. 13b can also be obtained by simulation as described above.

[0071] In step S105, based on the wavelength characteristics obtained in step S104, a specific wavelength (wavelength selection condition) to be selected by the wavelength selector (80) of the position detector (3) when manufacturing an article using the mold (7) is determined. The specific wavelength is the wavelength of light that the detector (33) must receive to efficiently detect the moiré pattern, as described above. The specific wavelength can be understood as a wavelength that can reduce the detection error of the detector (33) caused by the asymmetric shape of the mark (11) due to manufacturing error. The specific wavelength is not limited to a single wavelength but may be a wavelength band having a certain bandwidth. The wavelength band selected as the specific wavelength may be a single continuous wavelength band or may include multiple wavelength bands spaced apart from each other.

[0072] In step S106, information on a specific wavelength determined in step S105 is stored. As a storage location for the information on the specific wavelength, a storage unit (memory) of the controller (15) may be used. However, a device provided outside the imprint device (1) may be used. Thus, when manufacturing an article using the mold (7), the wavelength selector (80) (controller (15)) can select light of a specific wavelength from the diffracted light on the detection target (mark (10) and mark (11)) based on the information and guide it to the detector (33). That is, the relative position (position information) between the mark (10) and the mark (11) can be accurately detected while reducing the detection error of the detector (33) caused by the asymmetric shape of the mark (11) due to manufacturing error.

[0073] Further explanation regarding step S104 will be provided. Selecting the wavelength of light to be detected by the detector (33) as test light can be done by controlling the light induction / non-induction of each of the plurality of elements (pixels) of the wavelength selector (80) based on the first information described above. When generating wavelength characteristics (second information), it is preferable that the wavelength of the test light selected by the wavelength selector (80) and received by the detector (33) be changed sequentially from the short wavelength or long wavelength side. In addition, in order to stably measure light regardless of wafer manufacturing variations, a plurality of continuous wavelength bands considered to be somewhat valid based on optical simulation results or comparison results with an external measurement device may be selected as specific wavelengths.

[0074] To eliminate the rise time until stable oscillation, the light source unit (31a) (light source) can maintain a state where it can oscillate stably, or it can start at the timing of a step prior to step S104, taking into account the time until stabilization. Additionally, since the wavelength band of the illumination light from the light source unit (31a) is wide, the wavelength band can be narrowed using a wavelength cut filter before the light is incident as diffracted light on the wavelength selector (80). For example, a test light having a desired wavelength band can be generated by changing the combination of a short wavelength cut filter and a long wavelength cut filter. Furthermore, the wavelength of the light incident on the wavelength selector (80) can be finely controlled using a wavelength cut filter in which the transmission band changes continuously depending on the incident position of the light.

[0075] In the conventional method of changing the ratio of wavelengths of illumination light by changing the intensity of the light source itself of a specific wavelength of a semiconductor laser that mixes multiple wavelengths, a considerable amount of time is required because detection must begin after the light source has stabilized. Since it is practically difficult to wait for a long time while the imprint material (9) is cured, it is necessary to detect the location of the detection target by performing the imprint multiple times. However, in the method of selecting a wavelength by the wavelength selector (80), as in the present embodiment, the location of the detection target can be detected by switching the wavelength within tens of milliseconds, so data (e.g., wavelength characteristics) can be efficiently acquired using the time after the imprint.

[0076] Additionally, there are cases where the asymmetry of the mark shape changes between positions on the surface of the substrate (8) (e.g., between shot regions). Therefore, it is desirable that the wavelength of light (i.e., a specific wavelength) used to detect the position of the mark as a detection target be switched between positions on the surface of the substrate (8). In a conventional method of adjusting the output of each of the plurality of light sources (semiconductor lasers) included in the light source unit (31a), a considerable amount of time is required until the output stabilizes after adjusting the output of each light source. Therefore, it is difficult to rapidly switch the wavelength of light used to detect the position of the mark, and this may be disadvantageous in terms of throughput (productivity). On the other hand, in the position detector (3) according to the present embodiment, the wavelength of light used to detect the position of the mark can be rapidly switched by the wavelength selector (80) (liquid crystal filter (81)), so it may be advantageous in terms of throughput. In addition, when generating wavelength characteristics (second information), the time required to generate wavelength characteristics can be significantly reduced because the wavelength of the test light can be rapidly switched by the wavelength selector (80). If the time required to generate wavelength characteristics is reduced, more mark locations can be detected at the same detection time. Therefore, the time required to generate wavelength characteristics for each location on the surface of the substrate (8) can be reduced. That is, the time required to determine a specific wavelength for each location on the surface of the substrate (8) can be reduced.

[0077] As another method to reduce the time required to generate wavelength characteristics, a method of obtaining part of the necessary information through interpolation can be used. As an interpolation method, a fitting method can be used that performs fitting using results obtained by simulation based on a model having the same structure as the test sample. For example, when simulation results as shown in Fig. 13b are obtained, a function to approximate Fig. 13b is calculated. Using this function as the initial function of the fitting function, coefficients can be fitted using data obtained from actual measurements. Thus, a graph having the same trend as the simulation results can be plotted. The detection error of wavelengths that were not actually measured is calculated from the graph. Furthermore, a method of performing fitting by determining the initial fitting function based on actual measurement results under similar past process conditions, rather than using simulation results, is effective. This can reduce the error in the measurement values ​​even if the number of measurement points is reduced.

[0078] Wavelength characteristics can also be obtained by a simulation described with reference to FIGS. 13a and FIGS. 13b. The simulation can be executed by a controller (15) or by using a computer connected to the controller (15). In the simulation, it is necessary to consider the fact that if the asymmetric shape of the mark changes, a deviation occurs between the wavelength characteristics obtained by the simulation and the actual wavelength characteristics. This deviation can cause an error in the position information detected using a wavelength selection condition (specific wavelength) determined based on the wavelength characteristics.

[0079] A method to reduce errors arising from these reasons will be described. First, wavelength characteristics are obtained for multiple models. The multiple models are those with different asymmetric shapes (shape errors caused by manufacturing errors), and, for example, may be multiple models with different thicknesses or slopes of stacked layers. Next, based on the simulation results for each of the multiple models, the sensitivity of the detection error to the shape error is obtained for each wavelength. Next, the sensitivities obtained for the multiple models are added, and multiple wavelengths with low sensitivity to the shape error are selected as detection wavelengths.

[0080] The example shown in FIG. 13b is the result of performing a simulation assuming that the mark (10) and the mark (11) have no alignment error (a state where the position of the mark (10) and the position of the mark (11) are matched). Therefore, detection error = 0 nm is alignment error = 0. When forming a test sample in step S103, due to the asymmetric shape of the mark (11), a detection error may exist in the relative position between the mark (10) and the mark (11) detected by the position detector (3). Therefore, an alignment error may exist between the shot area of ​​the substrate (8) and the mold (7) that are aligned based on the relative position between the mark (10) and the mark (11) detected by the position detector (3). When an alignment error exists and the relative position between the mark (10) and the mark (11) is detected using multiple wavelengths in that state, a result is obtained in which an offset amount corresponding to the alignment error is added to the graph shown in FIG. 13b.

[0081] In order to obtain an offset amount from the result detected by the position detector (3), it is necessary to know the accurate relative position (alignment error) between the mark (11) and the mark (10). To this end, the alignment error in the test sample can be evaluated using an evaluation device such as an overlapping inspection device. The controller (15) obtains a wavelength characteristic with an offset amount corrected based on the wavelength characteristic obtained by the method described above and the evaluation result obtained using the evaluation device. If the simulation result shown in FIG. 13b is accurate, the corrected wavelength characteristic may be similar to the simulation result.

[0082] For example, when generating a test sample, if the alignment error between the mark (11) on the substrate (8) and the mark (10) on the mold (7) is 100 nm, the location of the detection error = 0 nm in FIG. 13b is actually measured as a location having an offset of 100 nm. When the test sample is evaluated by an evaluation device such as an overlapping inspection device, the overlapping error (alignment error) is evaluated as 100 nm.

[0083] In an imprint device (1) including a position detector (3) of the configuration described above, wavelength characteristics of a test sample can be obtained by steps S101 to S106 of the flowchart of FIG. 14. Here, regarding the wavelength characteristics obtained by detecting the position information of the test sample by the position detector (3), an offset value can be corrected based on an evaluation result obtained using an evaluation device such as an overlapping inspection device.

[0084] Further explanation regarding step S105 will be provided. As shown in the wavelength characteristics of FIG. 13b, the detection error changes according to the wavelength of the light received by the detector (33). The controller (15) determines a wavelength selection condition by the wavelength selector (80), more specifically, a specific wavelength (wavelength band) to be selected by the wavelength selector (80) so that the detection error of the position detector (3) (error in the position information detected by the position detector (3)) is reduced.

[0085] Hereinafter, a control example will be described for selecting a wavelength from illumination light generated by a white light laser light source (super continuum light source) forming a light source unit (31a) by means of a liquid crystal filter (81) functioning as a wavelength selector (80). The liquid crystal filter (81) functioning as a wavelength selector (80) is formed by a plurality of pixels (e.g., 640x480 pixels) arranged in two dimensions on an incident surface (80a) where diffracted light is incident, and the pixels can be individually turned on or turned off. That is, on the incident surface (80a) of the liquid crystal filter (81), pixels are controlled to be on / off so that the light beam is transmitted to the pixels placed at the position where light of a specific wavelength is incident, but not to the pixels placed at the remaining positions.

[0086] As described above, since the liquid crystal filter (81) (wavelength selector (80)) is positioned on the Fourier transform plane for the positions of the mark (10) and mark (11), light of different wavelengths arrives depending on the position on the incident plane (80a). FIG. 15 schematically shows the wavelength distribution (color distribution) of light incident on the incident plane (80a) of the liquid crystal filter (81) on the XY plane. The light arriving at the incident plane (80a) of the liquid crystal filter (81) is incident on different positions on the incident plane (80a) depending on the value of the wavelength λ. As a result, by selecting whether to transmit or block light at each position on the incident plane (80a) of the liquid crystal filter (81), the wavelength of light to be transmitted through the liquid crystal filter (81) and induced to the detector (33) can be selected. Additionally, in the liquid crystal filter (81), as shown in FIGS. 6a and 6b, by setting whether to continuously separate the light-transmitting region, the wavelength band to be induced in the detector (33) can be selected discretely or continuously. FIG. 6a shows an example in which light of one continuous wavelength band is selected, and FIG. 6b shows an example in which a plurality (two) wavelength bands spaced apart from each other are selected.

[0087] As described above, the position detector (3) according to the present embodiment includes a wavelength selector (80) having an incident plane (80a) in which a plurality of elements are arranged in two dimensions to switch the induction / non-induction of diffracted light to the detector (33). The wavelength selector (80) selects light of a specific wavelength from the diffracted light and induces it to the detector (33) by controlling each of the plurality of elements within the wavelength selector (80) according to the position where a specific wavelength is incident on the incident plane (80a). The position detector (3) including the wavelength selector (80) can rapidly switch the wavelength according to the position on the substrate where the detection target is provided. This may be advantageous in terms of throughput (productivity) compared to a conventional configuration in which the wavelength is selected by changing the output of the light source unit (31a).

[0088] <2nd Example>

[0089] A second embodiment according to the present invention will be described. In the first embodiment, an example using a liquid crystal filter (81) as a wavelength selector (80) was described. In the second embodiment, an example using an optical device as a wavelength selector (80) will be described, wherein a plurality of elements (pixels) that switch the reflection / non-reflection of diffracted light are arranged two-dimensionally on an incident plane (80a). As the optical device, a digital mirror device (DMD) (82) may be used. Note that the second embodiment basically follows the first embodiment and is identical to that described in the first embodiment, except for the matters described below.

[0090] In the position detector (3) according to the present embodiment, as shown in FIG. 3, a digital micromirror device (DMD) (82) is used instead of the aperture aperture (36) of the detection optical system (32), and the DMD (82) can function as a wavelength selector (80). The DMD (82) is formed by, for example, 640x480 multiple elements (devices or mirrors), and the reflection and non-reflection of diffracted light can be switched at each element. This allows for the selection of whether to guide the light beam to the detector (33) for each element of the DMD (82). When the DMD (82) is used as the wavelength selector (80), the diffraction efficiency is higher compared to when the liquid crystal filter (81) is used. In the configuration shown in FIG. 3, the DMD (82) is placed on the Fourier transform plane with respect to the surface of the substrate (8), and the light reflected by the DMD (82) is guided to the detector (33) (imaging device).

[0091] Here, the wavelength splitting of the illumination light will be described with reference to FIGS. 4a and 4b. As in the first embodiment, the primary light of the illumination light diffracted / wavelength split by the mark (10) and the mark (11) is incident on the DMD (82) as shown in FIGS. 4a and 4b. Since the DMD (82) is positioned on the Fourier transform plane, the light components incident on the DMD (82) are incident at different positions on the incident plane (80a) depending on the wavelength. Thus, as shown in FIGS. 16a and 16b, when controlling the state of each element of the DMD (82), light of a specific wavelength from the diffracted light can be selected and directed to the detector (33). Under the control of the controller (15), the DMD (82) selects whether to direct incident light to the detector (33) for each element (mirror) of the DMD (82).

[0092] The DMD (82) can change the optical path of the reflected light by changing the direction of the mirror as an element. As a result, in the DMD (82) functioning as a wavelength selector (80), the wavelength band to be induced to the detector (33) as a specific wavelength, as shown in FIGS. 16a and 16b, can be selected discretely or continuously by setting whether to continuously separate the region to reflect light and induce it to the detector (33). FIGS. 16a shows an example in which light of a single continuous wavelength band is selected and induced to the detector (33), and FIGS. 16b shows an example in which a plurality (2) of wavelength bands spaced apart from each other are selected and induced to the detector (33).

[0093] As described above, in this embodiment, a DMD (82) is used as a wavelength selector (80). Similar to the first embodiment, wavelength switching can be performed quickly according to the position on the substrate where the detection target is provided. This may be advantageous in terms of throughput (productivity) compared to the conventional configuration in which the wavelength is selected by changing the output of the light source unit (31a).

[0094] <Example of a method for manufacturing an article>

[0095] The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing an article, for example, a microdevice or a device having a microstructure such as a semiconductor device. The method for manufacturing an article according to the present embodiment includes a detection step of using a mark provided on a substrate as a detection target and detecting the position of the mark using the position detector (3) described above, and a positioning step of determining the position of the substrate based on the detection result in the detection step. In addition, the method for manufacturing an article according to the present embodiment includes a processing step of processing the substrate determined in the positioning step, and a manufacturing step of manufacturing an article from the substrate processed in the processing step. The processing step may include a step of forming a pattern on the substrate by the lithography device (imprint device (1)) described above. In addition, the manufacturing method includes other well-known steps (e.g., oxidation, deposition, deposition, doping, planarization, etching, resist stripping, dicing, bonding, and packaging, etc.). The method for manufacturing an article according to the present embodiment is superior to conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0096] When an imprint device is used as a lithography device, the pattern of the cured product formed using the imprint device is used permanently on at least a part of various articles or temporarily when manufacturing various articles. The articles are electrical circuit devices, optical devices, MEMS, recording devices, sensors, or molds, etc. Examples of electrical circuit devices are volatile or non-volatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, and semiconductor devices such as LSI, CCD, image sensors, and FPGAs. Examples of molds are molds for imprinting.

[0097] The pattern of the cured product is used as is as a component of at least some of the articles described above, or is used temporarily as a resist mask. After etching or ion implantation is performed in the substrate processing step, the resist mask is removed.

[0098] Next, a specific method for manufacturing the article will be described. As shown in FIG. 17a, a substrate (1z), such as a silicon wafer, is prepared on which a workpiece (2z), such as an insulator, is formed on the surface. Next, 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.

[0099] As shown in FIG. 17b, the side of the imprint mold (4z), which has a pattern formed with convex and concave portions, is positioned facing the imprint material (3z) on the substrate. As shown in FIG. 17c, the substrate (1z) to which the imprint material (3z) is applied and the mold (4z) are brought into contact with each other, 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 curing energy is applied to the imprint material (3z) through the mold (4z), the imprint material (3z) is cured.

[0100] As shown in FIG. 17d, after the imprint material (3z) is cured, the mold (4z) is separated from the substrate (1z). Then, 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, a pattern having the convex and concave parts of the mold (4z) is transferred to the imprint material (3z).

[0101] As shown in FIG. 17e, by performing etching using the pattern of the cured material as an etching mask, the portion of the surface of the workpiece (2z) where the cured material is absent or thinly remaining is removed to form a groove (5z). As shown in FIG. 17f, by removing the pattern of the cured material, an article with grooves (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 a component of the article, such as an interlayer insulating film included in a semiconductor device, for example.

[0102] <Other Examples>

[0103] Embodiments of the present invention may also be realized by a computer of a system or device comprising one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing the functions of one or more of the embodiments(s), by reading and executing computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may be more fully referred to as a 'non-transient computer-readable storage medium'), and / or by a method performed by the computer of the system or device by reading and executing computer-executable instructions from the storage medium to perform the functions of one or more of the embodiments(s) and / or by controlling one or more circuits to perform the functions of one or more of the embodiments(s). The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)) and may include a network of individual computers or individual processors for reading and executing computer-executable instructions. Computer-executable instructions may be provided to the computer, for example, from a network or a storage medium. Storage media include, for example, hard disks, random access memory (RAM), read-only memory (ROM), storage in distributed computing systems, and optical discs (e.g., compact discs (CD), digital multifunction discs (DVD), or Blu-ray discs (BD)). TM It may include one or more of the following: an optical disc, a flash memory device, a memory card, etc.

[0104] (Other examples)

[0105] The present invention can be realized in a process in which a program realizing one or more functions of the above embodiments is supplied to a system or device via a network or storage medium, and one or more processors in a computer of the system or device read and execute the program.

[0106] In addition, it can also be implemented by a circuit that realizes one or more functions (e.g., an ASIC).

[0107] 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 should be interpreted in the broadest sense to include structures and functions equivalent to all such variations.

Claims

Claim 1 A detection device for detecting the position of a detection target including a diffraction grating pattern, comprising: an illuminator configured to illuminate the detection target with illumination light including multiple wavelengths; and a wavelength selector configured to select light of a specific wavelength from the diffraction light, the incident surface on which diffraction light from the detection target illuminated by the illuminator is incident. A detection device comprising a detector configured to receive light of a specific wavelength selected by the wavelength selector and to detect the position of the detection target, wherein a plurality of elements are arranged in two dimensions on the incident surface of the wavelength selector, each switching the induction / non-induction of the diffracted light to the detector, the diffraction directions of the plurality of light components of wavelengths included in the illumination light on the detection target are different from each other, and the positions on the incident surface of the wavelength selector where the light components are incident as diffracted light are different from each other, and the wavelength selector selects the light of the specific wavelength from the diffracted light and induces the light to the detector by controlling each of the plurality of elements according to the position on the incident surface where the light of the specific wavelength is incident, and the wavelength selector acquires a wavelength where the detection target cannot be detected based on information representing the relationship between each of the plurality of wavelengths and the detection error at the detector, and determines the specific wavelength in a wavelength band excluding the acquired wavelength so as to reduce the detection error. Claim 2 A detection device according to claim 1, further comprising a lens configured to cause the plurality of light components of wavelengths diffracted by the detection target to be incident at different positions on the incident plane and to be provided between the wavelength selector and the detection target. Claim 3 In claim 1, the wavelength selector is a detection device comprising an optical device configured to switch the transmission / non-transmission of the diffracted light at each of the plurality of elements. Claim 4 In claim 1, the wavelength selector comprises a detection device including an optical device configured to switch the reflection / non-reflection of the diffracted light at each of the plurality of elements. Claim 5 In claim 1, the illuminator is a detection device that obliquely illuminates the detection target with the illuminant light. Claim 6 In claim 1, the wavelength selector is a detection device that controls each of the plurality of elements so that light of the specific wavelength is selected from the diffracted light and guided to the detector based on information indicating the relationship between each of the plurality of wavelengths and the incident position on the incident plane. Claim 7 In claim 1, the wavelength selector is a detection device that is a digital mirror device. Claim 8 In claim 1, the wavelength selector is a detection device that generates information indicating the relationship between each of the plurality of wavelengths and the detection error in the detector by changing the wavelength selected from the plurality of wavelengths and acquiring the detection error of the detector. Claim 9 In claim 1, the detection target includes a plurality of regions whose positions are detected by the detection device, and the wavelength selector is a detection device that changes the specific wavelength between the plurality of regions. Claim 10 A lithography apparatus for forming a pattern on a substrate, comprising: a detection device defined in any one of claims 1 to 9, configured to detect the position of said mark by using a mark provided on the substrate as a detection target; and a mechanism configured to determine the position of said substrate based on the detection result of said detection device. Claim 11 A method for manufacturing an article, comprising: a step of using a mark provided on a substrate as a detection target to detect the position of said mark by a detection device defined in any one of claims 1 to 9; a step of determining the position of said substrate based on the detection result in the detection step; a step of processing said substrate determined in the positioning step; and a step of manufacturing an article from said substrate processed in the processing step.

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