Detection device, lithography apparatus, and article manufacturing method

Abstract

A detection device detects the relative position between a first mark and a second mark that overlap each other. The device includes a lighting system configured to illuminate the first and second marks with lighting light, and a detection system configured to form an image on an imaging surface from diffracted light from the first and second marks, configured to form optical information indicating the relative position in a first or second direction on the imaging surface of an image sensor. The lighting light passes only through the optical axis of the lighting system on the pupil surface of the lighting system. A light-blocking body provided on the pupil surface of the detection system includes a first light-blocking part that crosses the optical axis of the detection system in a direction conjugated to the first direction, and a second light-blocking part that crosses the optical axis of the detection system in a direction conjugated to the second direction.

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] An imprint device forms a pattern consisting of a cured imprint material by contacting a mold with an imprint material placed on a substrate and curing the imprint material. In such an imprint device, it is important to accurately align the substrate and the mold. Japanese Patent Publication No. 2008-522412 describes a technique for aligning a substrate and a mold using a mark formed by a diffraction grating provided on the substrate and a mark formed by a diffraction grating provided on the mold.

[0003] When illuminating a mark, light reflected by the edge, which is the boundary between the mark and the area outside the mark, is incident on the image sensor as noise light, which can reduce the detection precision of the mark. In particular, when the area of ​​the mark is reduced, the influence of noise light on the image formed by the light for detecting position information from the mark increases, and thus the reduction in detection precision can become significant. The problem to be solved

[0004] The present invention provides a technique advantageous for detecting the relative position between a first mark and a second mark provided on a first object and a second object, respectively, with high detection precision. means of solving the problem

[0005] One embodiment of the present invention provides a detection device for detecting a relative position between a first mark and a second mark provided on a first object and a second object, respectively, arranged to overlap each other, wherein the detection device includes a lighting system configured to illuminate the first mark and the second mark with lighting light; and an image sensor, wherein the detection device is configured to form an image on the imaging surface of the image sensor from diffracted light from the first mark and the second mark illuminated by the lighting system, wherein the first mark and the second mark are configured to form optical information indicating a relative position in a first direction or a second direction orthogonal to the first direction on the imaging surface, and the lighting light is light that passes only through the optical axis of the lighting system and the vicinity of the optical axis on the pupil surface of the lighting system, and the pupil surface of the detection system is provided with a light-blocking body comprising a first light-blocking part that crosses the optical axis of the detection system in a direction parallel to a third direction and a second light-blocking part that crosses the optical axis of the detection system in a direction parallel to a fourth direction, wherein the third direction is a direction conjugated to the first direction and the fourth direction is a direction conjugated to the second direction.

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

[0007] Figure 1a is a diagram illustrating the light intensity distribution of the pupil surface of a lighting system. Figure 1b is a diagram illustrating the light intensity distribution of the pupil surface of a detection system. Figure 2 is a drawing illustrating the configuration of an imprint device as an example of a lithography device. Figure 3 is a diagram illustrating the configuration of a detection device. Figure 4a is a drawing illustrating a mold mark. Figure 4b is a drawing illustrating a substrate mark. FIGS. 5a to 5d are drawings illustrating a diffraction grating that generates moiré patterns. Figures 6a and 6b are drawings illustrating a diffraction grating that generates moiré patterns. Figure 7 is a drawing illustrating pattern edge light. FIG. 8a is a drawing illustrating a lighting aperture placed on the pupil plane of a lighting system. FIG. 8b is a diagram illustrating an illumination aperture placed on the pupil surface of a detection system. Figures 9a and 9b are diagrams illustrating the effect of the presence or absence of pattern edge light on moiré pattern phase difference measurement. FIGS. 10a to 10f are drawings illustrating a 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 do not limit the scope of the claimed invention. Although numerous features are described in the embodiments, the invention is not limited to requiring all such features, and numerous such features may be appropriately combined. Furthermore, in the accompanying drawings, identical or similar components are assigned the same reference number, and redundant descriptions thereof are omitted.

[0009] FIG. 2 shows the configuration of an imprint device (10) as an example of a lithography device for transferring a pattern of a plate onto a substrate. The imprint device (10) is used in the manufacture of devices such as semiconductor devices, and forms a pattern on a substrate (17) that is a workpiece, consisting of a cured imprint material (18), by molding an uncured imprint material (18) on a substrate (17) using a mold (16). The pattern formation process of forming a pattern on a substrate (17) by the imprint device (10) may include a contact step, a filling and alignment step, a curing step, and a separation step. In the contact step, the imprint material (18) on the shot area of ​​the substrate (17) and the pattern area (16a) of the mold (16) come into contact with each other. In the filling and alignment step, an imprint material (18) is filled into the space formed by the shot area of ​​the substrate (17) and the pattern area (16a) of the mold (16), and the shot area of ​​the substrate (17) and the pattern area (16a) of the mold (16) are aligned. The shot area is an area where a pattern is formed by a single pattern formation process. That is, the shot area is an area where the pattern area (16a) of the mold (16) is transferred by a single pattern formation process.

[0010] As an imprint material, a curable composition (also referred to as an uncured resin) that is cured by receiving 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 (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. The imprint material can be supplied in the form of a film onto a substrate by a spin coater or a slit coater. The viscosity of the imprint material (viscosity at 25°C) may be, for example, 1 mPa·s (inclusive) to 100 mPa·s (inclusive). As the material of the substrate, for example, glass, ceramic, metal, semiconductor (Si, GaN, SiC, etc.), resin, etc. may be used. If necessary, a component made of a material different from the substrate may be provided on the surface of the substrate. The substrate is, for example, a silicon wafer, a compound semiconductor wafer, or silica glass. Below, examples of employing a photocurable composition as the imprint material are described, but this is not intended to limit the type of imprint material.

[0011] In this specification and the accompanying drawings, directions are indicated in an XYZ coordinate system in which the direction parallel to the surface of the substrate (17) is the XY plane. The 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 regarding the X-axis, Y-axis, and Z-axis means control or driving regarding the direction parallel to the X-axis, the direction parallel to the Y-axis, and the direction parallel to the Z-axis, respectively. Furthermore, control or driving regarding the θX-axis, θY-axis, and θZ-axis means control or driving regarding rotation around an axis parallel to the X-axis, rotation around an axis parallel to the Y-axis, and rotation around an axis parallel to the Z-axis, respectively. Additionally, position is information that can be specified based on coordinates of the X-axis, Y-axis, and Z-axis, and attitude is information that can be specified by values ​​of the θX-axis, θY-axis, and θZ-axis. Positioning means controlling the position and / or attitude. Alignment (positioning) may include controlling the position and / or orientation of at least one of the substrate (17) and the mold so as to reduce the alignment error (overlap error) between the shot area of ​​the substrate (17) and the pattern area of ​​the mold (16). Additionally, alignment may include control to correct or change the shape of at least one of the shot area of ​​the substrate (17) and the pattern area of ​​the mold (16). The contact step and the separation step may be executed by driving the mold (16) by the mold driving mechanism (13), but may also be executed by driving the substrate (17) by the substrate driving mechanism (14). Alternatively, the contact step and the separation step can be performed by driving the mold (16) by the mold driving mechanism (13) and driving the substrate (17) by the substrate driving mechanism (14).

[0012] The imprint device (10) may include a curing unit (11), a detection device (12), a mold driving mechanism (13), a substrate driving mechanism (14), and a control unit (C). The imprint device (10) may further include a coating unit (15). The curing unit (11) cures the imprint material (18) by irradiating light, such as ultraviolet light as curing energy, onto the imprint material (18) after a contact step in which the mold (16) is brought into contact with the imprint material (18) on the substrate (17). The curing unit (11) includes, for example, a light source and a plurality of optical elements for uniformly irradiating the light emitted from the light source onto a pattern area (16a) of the mold (16) as the irradiated surface in a predetermined shape. In particular, it is preferable that the irradiation area (irradiation range) of light by the curing unit (11) has a surface area that is nearly equal to or slightly larger than the surface area of ​​the pattern area (16a). This is to prevent a situation in which the mold (16) or substrate (17) expands due to heat generated by irradiation, thereby causing misalignment or distortion of the pattern transferred to the imprint material (18), by ensuring that the irradiation area has a minimum required area. Additionally, this is to prevent a situation in which light reflected by the substrate (17), etc., reaches the coating unit (15) and cures the imprint material (18) remaining in the discharge part of the coating unit (15), thereby preventing an abnormality in the operation of the coating unit (15). As a light source, for example, a high-pressure mercury lamp, various excimer lamps, an excimer laser, or a light-emitting diode may be employed. The light source can be appropriately selected according to the characteristics of the imprint material (18) which is the light receiver.

[0013] FIG. 3 shows an example of the configuration of a detection device (12). The detection device (12) is configured to optically detect or measure the relative position between a mold mark (first mark) (19) placed on a mold (first object) (16) and a substrate mark (second mark) (20) placed on a substrate (second object) (17). The mold mark (first mark) (19) and the substrate mark (second mark) (20) are configured to form optical information indicating the relative position in the X direction (first direction) or the Y direction (second direction) on the imaging surface of an image sensor (25) (described later). The detection device (12) may include a lighting system (22) and a detection system (21). The lighting system (22) and the detection system (21) may share some components. The illumination system (22) includes a light source (23) and generates illumination light using light from the light source (23), and illuminates the measurement target (first mark and second mark) by the illumination light. This illumination light may be unpolarized light. The detection system (21) detects the relative position between the mold mark (first mark) (19) and the substrate mark (second mark) (20) as the measurement target by detecting light from the measurement target illuminated by the illumination light.

[0014] Among the optical axes of the detection device (12), the optical axis at the position of the substrate (17) and the mold (16) is perpendicular to the upper surface of the substrate (17) and the lower surface of the mold (16) (pattern area (16a)), that is, parallel to the Z-axis. The detection device (12) may be configured to be driven in the X direction and the Y direction by a driving mechanism (not shown) according to the position of the mold mark (19) and the substrate mark (20). The detection device (12) may be configured to be driven in the Z direction to align the focus of the detection system (21) to the position of the mold mark (19) or the substrate mark (20). The detection device (12) may include an optical element or an optical system for focus alignment. Based on the relative position between the mold mark (19) and the substrate mark (20) detected or measured using the detection device (12), the positioning of the substrate (17) by the substrate driving mechanism (14) and the correction of the shape and magnification of the pattern area (16a) by the correction mechanism (not shown) can be controlled. The correction mechanism is mounted on the mold driving mechanism (13) and can adjust the shape and magnification of the pattern area (16a) of the mold (16) by deforming the mold (16). The mold mark (19) and the substrate mark (20) will be described in detail later.

[0015] The mold driving mechanism (13) may include a mold chuck (not shown) that holds and supports the mold (16) by vacuum suction force or electrostatic force, and a mold driving unit (not shown) that drives the mold (16) by driving the mold chuck. The mold driving mechanism (13) may include the aforementioned correction mechanism. The mold driving unit may be configured, for example, to drive the mold chuck or the mold (16) with respect to the Z-axis. The mold driving unit may also be configured to drive the mold chuck or the mold (16) with respect to at least one of the θX-axis, θY-axis, θZ-axis, X-axis, and Y-axis.

[0016] The substrate driving mechanism (14) may include a substrate chuck that holds and supports the substrate (17) by vacuum suction force or electrostatic force, and a substrate driving unit (not shown) that drives the substrate (17) by driving the substrate chuck. The substrate driving unit may be configured, for example, to drive the substrate chuck or the substrate (17) with respect to the X-axis, Y-axis, and θZ-axis. The substrate driving unit may also be configured to drive the substrate chuck or the substrate (17) with respect to at least one of the θX-axis, θY-axis, and Z-axis.

[0017] The dispensing unit (dispenser) (15) applies or places an uncured imprint material (18) on a substrate (17). The dispensing unit (15) may be placed outside the housing of the imprint device (10). In this case, the dispensing unit (15) may be understood as a component that is not a component of the imprint device (10).

[0018] The mold (16) includes a pattern, such as a circuit pattern, to be transferred to a substrate (17) (an imprint material (18) on the same) in a pattern area (16a). The mold (16) may be made of a material that transmits light as curing energy, for example, quartz. The substrate (17) may be a semiconductor substrate, for example, a single-crystal silicon substrate, or a substrate comprising at least one layer on a semiconductor substrate.

[0019] The control unit (C) may be configured to control the curing unit (11), the detection device (12), the mold driving mechanism (13), the substrate driving mechanism (14), and the coating unit (15). The control unit (C) may be formed, for example, by a Field Programmable Gate Array (FPGA), a computer with a built-in program, or a combination of all or part of these components. The FPGA may include a Programmable Logic Device (PLD) or an Application Specific Integrated Circuit (ASIC). The control unit (C) may include memory and a processor, and may define the operation and function of the imprint device (10) by operating based on an arithmetic expression, parameters, and computer programs stored (preserved) in the memory. At least part of the function of the detection device (12), for example, the function of processing an image captured by an image sensor (25), may be provided by a module built into the control unit (C). In this case, the module of the control unit (C) may be understood as part of the detection device (12).

[0020] Now, an imprint process or pattern formation process executed by the imprint device (10) will be described. First, a substrate (17) is conveyed to the substrate chuck of the substrate driving mechanism (14) by a substrate conveying mechanism (not shown) and fixed to the substrate chuck. Subsequently, the substrate (17) is driven by the substrate driving mechanism (14) so ​​that the shot area of ​​the substrate (17) moves to a coating position by the coating unit (15). After that, the coating unit (15) applies, places, or supplies an imprint material (18) to the shot area (imprint area) of the substrate (coating step).

[0021] Next, the substrate (17) is driven by the substrate driving mechanism (14) so ​​that the shot area where the imprint material (18) is placed is positioned directly below the pattern area (16a) of the mold (16). Then, for example, the mold driving mechanism (13) lowers the mold (16) to bring the imprint material (18) on the substrate (17) and the pattern area (16a) of the mold (16) into contact with each other (contact step). By doing so, the imprint material (18) is filled into the space between the substrate (17) and the pattern area (16a) of the mold (16) (including the concave portion of the pattern area (16a)) (filling step). Additionally, for a plurality of mark pairs formed by the mold mark (19) and the substrate mark (20), the relative position between the mold mark (19) and the substrate mark (20) is detected or measured using a detection device (12). Based on the result, the pattern area (16a) and the shot area of ​​the substrate (17) are aligned (alignment step). At this time, the shape of the pattern area (16a) of the mold (16) can be corrected using a correction mechanism. Additionally, the shape of the shot area of ​​the substrate (17) can be corrected using a heating mechanism (not shown).

[0022] Upon completion of the filling and alignment steps, the curing unit (11) irradiates light onto the imprint material (18) through the mold (16), thereby curing the imprint material (18) (curing step). At this time, the detection device (12) can be driven to retract so as not to block the light path of the curing unit (11). Subsequently, the mold driving mechanism (13) separates the mold (16) from the cured imprint material (18) on the substrate (17) by raising the mold (16) (separation step).

[0023] The imprint device (10) can be understood as an example of a lithography device comprising a detection device (12), aligning a plate (or pattern area) and a substrate (or shot area) based on the output from the detection device (12), and transferring the pattern of the plate to the substrate. The imprint device (10) aligns a mold (16) (first object or plate) provided with a mold mark (19) (first mark) and a substrate (17) (second object) provided with a substrate mark (20) (second mark) based on the output from the detection device (12).

[0024] Hereinafter, details of the detection device (12) will be described with reference to FIG. 3. As previously described, the detection device (12) includes a lighting system (22) and a detection system (21), and the lighting system (22) and the detection system (21) may share some components. The lighting system (22) directs the illumination light generated by light from a light source (23) through a prism (24) to a common optical axis, thereby illuminating the mold mark (19) and the substrate mark (20). The light source (23) may include, for example, at least one of a halogen lamp, an LED, a semiconductor laser (LD), a high-pressure mercury lamp, a metal halide lamp, a supercontinuum light source, and a Laser-Driven Light Source (LDLS). The wavelength of the illumination light generated by the light source (23) is selected so as not to cure the imprint material (18).

[0025] A prism (24) is shared by an illumination system (22) and a detection system (21) and may be positioned on or near the pupil surface (1) of the illumination system (22) or on or near the pupil surface (2) of the detection system (21). Each of the mold mark (19) and the substrate mark (20) may include a mark formed by a diffraction grating. The detection system (21) may form an optical image of interference light (interference pattern or moiré pattern) generated by interference between light diffracted by the mold mark (19) and the substrate mark (20) illuminated by the illumination system (22) on the imaging surface of an image sensor (25). The image sensor (25) may be formed, for example, by a CCD sensor or a CMOS sensor.

[0026] The prism (24) includes a surface (bonding surface) obtained by joining two members as a reflective surface (RS), and may include a reflective film (24a) on the bonding surface. The prism (24) may be replaced with a plate-shaped optical element having a reflective film (24a) on its surface. The location where the prism (24) is placed does not need to be the pupil surface (1) of the illumination system (22) or the vicinity thereof, or the pupil surface (2) of the detection system (21) or the vicinity thereof. An illumination aperture (27) (e.g., a pinhole plate) may be placed on the pupil surface (1) of the illumination system (22). A detection aperture (26) may be placed on the pupil surface (2) of the detection system (21). The illumination aperture (27) defines the light intensity distribution of the pupil surface (1) of the illumination system (22). Note that the illumination aperture (27) is an optional component, and that illumination light parallel to the optical axis can be formed by defining the area of ​​the reflective film (24a).

[0027] FIG. 4a is a schematic diagram of a mold mark (19) as an alignment mark. FIG. 4b is a schematic diagram of a substrate mark (20) as an alignment mark. The mold mark (19) can be formed, for example, by a mark (19a) and a diffraction grating (19b, 19b'). The substrate mark (20) can be formed, for example, by a mark (20a) and a diffraction grating (20b, 20b'). The marks (19a, 20a) are rough detection marks, and the diffraction grating (19b, 19b', 20b, 20b') are fine detection marks.

[0028] Each of the diffraction gratings (19b, 19b', 20b, 20b') may contain a periodic pattern. By referring to the geometric center positions of the mark (19a) and the mark (20a), the relative position between the mold (16) and the substrate (17) can be obtained from the detection result of the detection device (12). Since interference patterns (moiré patterns) are generated by diffracted light from the diffraction gratings (19b)(19b') of the mold mark (19) and the diffraction gratings (20b)(20b') of the substrate mark (20), the amount of light of the moiré pattern changes according to the diffraction efficiency of the mold mark (19) and the substrate mark (20). In particular, since the diffraction efficiency changes periodically according to the change in wavelength, there may be 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 become noise.

[0029] FIGS. 5a to 5d are drawings illustrating examples of diffraction gratings that generate moiré patterns. Hereinafter, with reference to FIGS. 5a to 5d, the principle of generating moiré patterns by diffracted light from diffraction gratings (19b and 20b) and the detection of the relative position between diffraction gratings (19b) and diffraction gratings (20b) using moiré patterns will be explained. The period of the pattern (grid) in the measurement direction of the diffraction grating (19b) provided on the mold (16) and the diffraction grating (20b) provided on the substrate (17) is slightly different from each other. When two diffraction gratings having different periods are overlapped, due to interference between the diffracted light from the two diffraction gratings, a pattern having a period that reflects the difference in period between the diffraction gratings, that is, a so-called moiré pattern (moiré), appears. At this time, since the phase of the moiré pattern changes depending on the relative position between the diffraction gratings, the relative position between the diffraction grating (19b) and the diffraction grating (20b), that is, the relative position between the mold (16) and the substrate (17), can be obtained by detecting the moiré pattern.

[0030] More specifically, when different diffraction gratings (19b) and diffraction gratings (20b) having slightly different periods are overlapped, the diffracted light from the diffraction gratings (19b, 20b) overlaps with each other, thereby producing a moiré pattern with a period that reflects the difference in periods, as shown in FIG. 5c. In the moiré pattern, the position of the light and dark areas (phase of the stripes) changes depending on the relative position between the diffraction grating (19b) and the diffraction grating (20b). For example, if one of the diffraction gratings (19b, 20b) is offset in the X direction, the moiré pattern shown in FIG. 5c changes into the moiré pattern shown in FIG. 5d. Since the moiré pattern occurs as a pattern with a large period by magnifying the actual positional misalignment between the diffraction grating (19b) and the diffraction grating (20b), the relative position between the diffraction grating (19b) and the diffraction grating (20b) can be detected with high precision even if the resolution of the detection system (21) is low. The diffraction gratings (19b, 19b', 20b, 20b') were described using a one-dimensional diffraction grating pattern. However, for example, a checkerboard pattern can be used for the diffraction gratings (20b, 20b'), as shown in FIG. 6b. By using a checkerboard pattern as the diffraction grating pattern, light can be diffracted in the X direction as well as in the Y direction shown in FIG. 4a and FIG. 4b.

[0031] If there is scattered light from pattern edges and scattered light from foreign matter, these cause measurement errors in moiré measurement. When illumination light is incident on the alignment mark from the Z direction perpendicular to the XY plane, noise light passes through the X-axis and Y-axis of the pupil surface (2) of the detection system (21). This is because the edges of the patterns of the mold mark (19) and the substrate mark (20) are parallel to one of the X-axis and Y-axis. Therefore, it is desirable to detect light passing through an eccentric region from the center of the pupil of the detection system (21) as a signal required for detecting moiré patterns using an image sensor (25), and to block noise light incident on the X-axis and Y-axis of the pupil of the detection system (21). By doing so, noise caused by scattered light from pattern edges can be reduced. Additionally, if each of the two opposing sides of the checkerboard pattern is not parallel to either the X-axis or the Y-axis, scattered light from the pattern edges may pass through axes other than the X-axis and Y-axis of the pupil surface (2) of the detection system (21). Therefore, it is preferable that each pattern edge be parallel to either the X-axis or the Y-axis. This is not limited to cases where the diffraction grating pattern of the substrate mark (20) is a checkerboard pattern and the diffraction grating pattern of the mold mark (19) is a line-and-space pattern. For example, the diffraction grating pattern of the substrate mark (20) may be a line-and-space pattern and the diffraction grating pattern of the mold mark (19) may be a checkerboard pattern.

[0032] Next, a method for determining relative positions by detecting moiré patterns is described. The diffraction gratings (19b, 20b) are formed in a periodic pattern, and the period of the measurement direction is slightly different. Therefore, when these diffraction gratings are overlapped, a moiré pattern is formed in which the light intensity changes in the Y direction. In addition, due to the difference in period between the diffraction grating (19b) and the diffraction grating (20b), the direction of displacement of the moiré pattern when the relative position changes is different. For example, if the period of the diffraction grating (19b) is slightly larger than the period of the diffraction grating (20b), and the substrate (17) is relatively displaced in the +Y direction, the moiré pattern is also displaced in the +Y direction. On the other hand, if the period of the diffraction grating (19b) is slightly smaller than the period of the diffraction grating (20b), and the substrate (17) is relatively displaced in the +Y direction, the moiré pattern is displaced in the -Y direction.

[0033] The diffraction gratings (19b', 20b') form different moiré patterns. The relationship between the periods of the diffraction grating (19b) and the diffraction grating (20b) is opposite to the relationship between the periods of the diffraction grating (19b') and the diffraction grating (20b'). Therefore, when the relative position changes, the positions of the two measured moiré patterns change in opposite directions. If the periodic marks on the mold side and the substrate side that generate the moiré pattern are misaligned by one period, the misalignment of one period cannot be detected according to the moiré pattern detection principle. Therefore, by using marks (19a, 20a) with low detection precision, it can be confirmed that there is no relative positional misalignment of one period between the mold (16) and the substrate (17).

[0034] Next, with reference to FIGS. 1a and 1b, the light intensity distribution in the pupil surface (1) of the illumination system (22) and the pupil surface (2) of the detection system (21) will be described by example. As illustrated in FIG. 1a, at the exit of the pupil surface (1) of the illumination system (22), a light intensity distribution (3) having light intensity concentrated at the intersection of the x-axis and y-axis (i.e., the optical axis) can be generated. FIG. 1b illustrates a light intensity distribution formed in the pupil surface (1) of the detection system (21) by diffracted light (4a to 4d, 5a to 5d, 6) from a diffraction grating (19b, 20b) (19b', 20b') illuminated by the light intensity distribution (3). An xyz coordinate system is defined as the coordinate system of the pupil surface (1) of the illumination system (22). The x-axis and y-axis of the pupil surface (1) of the lighting system (22) correspond to the Z-axis and Y-axis of the XYZ coordinate system, respectively. The x-direction parallel to the x-axis is a direction conjugated to the X-direction parallel to the X-axis, and the y-direction parallel to the y-axis is a direction conjugated to the Y-direction parallel to the Y-axis. In the lighting system (22), when the x-direction and the X-direction are conjugated to each other, this means that the x-direction and the X-direction correspond to each other in the case where there is no reflective surface (e.g., reflective surface (RS)) that bends the optical axis of the lighting system (22) between the mold (16) / substrate (17) and the pupil surface (1) of the lighting system (22). In the lighting system (22), when the x direction and the X direction are conjugated with each other, this means that if there is a reflective surface between the mold (16) / substrate (17) and the pupil surface (1) that bends the optical axis, the X direction mapped to the pupil surface (1) by the reflective surface coincides with the x direction. When a reflective surface is present, the x direction may or may not coincide with the X direction. This is also the same for the conjugation of the y direction with respect to the Y direction.

[0035] In the example shown in FIG. 3, there is no reflective surface between the mold (16) / substrate (17) and the pupil surface (2) of the detection system (21) that bends the optical axis of the detection system (21). Therefore, if the xyz coordinate system is defined as the coordinate system of the pupil surface (2) of the detection system (21), the x-axis coincides with the X-axis and the y-axis coincides with the Y-axis. The x-direction (third direction) parallel to the x-axis is a direction conjugated to the X-direction (first direction) parallel to the X-axis, and the y-direction (fourth direction) parallel to the y-axis is a direction conjugated to the Y-direction (second direction) parallel to the Y-axis. In the detection system (21), when the x direction and the X direction are conjugated with each other, this means that the x direction and the X direction coincide with each other in the case where there is no reflective surface between the mold (16) / substrate (17) and the pupil surface (2) of the detection system (21) that bends the optical axis of the detection system (21). In the detection system (21), when the x direction and the X direction are conjugated with each other, this means that when there is a reflective surface between the mold (16) / substrate (17) and the pupil surface (2) of the detection system (21) that bends the optical axis, the X direction mapped to the pupil surface (2) by the reflective surface coincides with the x direction. When a reflective surface exists, the x direction may or may not coincide with the X direction. This is also the same for the conjugation of the y direction with respect to the Y direction.

[0036] Now, the case where the measurement direction (the direction in which the light intensity in the moiré pattern changes) coincides with the X direction (first direction) is described. The relative position between the diffraction grating (19b)(19b') of the mold mark (19) and the diffraction grating (20b)(20b') of the substrate mark (20) is equivalent to the relative position between the mold mark (19) and the substrate mark (20). The detection system (21) forms an image on the imaging surface of the image sensor (25) from information indicating the relative position between the diffraction grating (19b)(19b') of the mold mark (19) and the diffraction grating (20b)(20b') of the substrate mark (20) in the measurement direction.

[0037] When a light intensity distribution (3) is formed at the exit of the pupil surface (1) of the lighting system (22), having light intensity concentrated at the intersection of the X-axis and Y-axis (the optical axis of the lighting system (22)) and its vicinity, in other words, consider the case where the lighting light passes only through the optical axis of the lighting system (22) and its vicinity at the pupil surface (1) of the lighting system (22). In this case, it can be considered that among the light emitted from the light source (23), only the light component parallel to the optical axis is incident on the mold mark (19) (diffraction grating (19b, 19b')) as lighting light. At the mold mark (19) (diffraction grating (19b, 19b')), +1st order diffracted light and -1st order diffracted light are generated in the X-axis direction. Among the diffracted light generated by the mold mark (19) (diffracting grating (19b, 19b')), the +1st order diffracted light is light that is diffracted in the positive direction of the X-axis with respect to the optical axis, and the -1st order diffracted light is light that is diffracted in the negative direction of the X-axis with respect to the optical axis. When each diffracted light is incident on the substrate mark (20) (diffracting grating (20b, 20b')), the +1st order diffracted light and the -1st order diffracted light are generated. Since the substrate mark (20) includes a checkerboard pattern, the propagation direction of the light diffracted by the substrate mark (20) has both an X-axis component and a Y-axis component. Among the diffracted light generated by the substrate mark (20), the +1st order diffracted light is diffracted light that includes a positive component of the Y-axis with respect to the optical axis in the propagation direction, and the -1st order diffracted light is diffracted light that includes a negative component of the Y-axis with respect to the optical axis in the propagation direction.

[0038] Referring to FIGS. 1a and 1b, for example, at the pupil surface (2) of the detection system (21), the diffracted light (4a) represents light obtained when illumination light is incident on the mold mark (19), diffracted in the -1st order direction, and diffracted at the substrate mark (20) in the +1st order direction. This diffracted light (4a) is represented as (-1, +1). According to this representation method, in addition to the diffracted light (-1, +1), diffracted light (4b) (+1, +1), diffracted light (4c) (-1, -1), and diffracted light (4d) (+1, -1) are incident on the pupil surface (2). An image is formed on the imaging surface of the image sensor (25) from the diffracted light (4a, 4b), thereby generating an interference pattern (moiré pattern) in which the light intensity changes in the X direction. Likewise, interference patterns are generated in which the light intensity changes in the X direction by the diffracted light (4c, 4d).

[0039] The pitch of the mold mark (19) (19b, 19b') is denoted as Pmx, and the pitches in the X and Y directions of the substrate mark (20) (20b, 20b') are denoted as Pwx and Pwy, respectively. The distance from the X-axis of the diffracted light (4a) at the pupil plane (2) of the detection system (21) can be given by f·tanθwy, where f represents the focal length of the lens group placed between the pupil plane (2) of the detection system (21) and the mold mark (19) / substrate mark (20), and θwy represents the diffraction angle in the Y direction at the substrate mark (20). The diffraction angle (θwy) is arcsin(λ / Pwy). This is because the diffraction angle (θ) can be given by sinθ=λ / p when λ represents the wavelength of light and p represents the mark pitch. The wavelength (λ) may be a single wavelength, such as when using a laser light source, for example, or may have an intensity distribution in the wavelength band of 500 to 800 nm. Meanwhile, the distance from the Y-axis of the diffracted light (4a) can be given by f·tan(θmx-θwx), where θmx represents the diffraction angle in the X-axis direction at the mold mark (19) and θwx represents the diffraction angle in the X-axis direction at the substrate mark (20). θmx-θwx is arcsin(λ / Pmx)-arcsin(λ / Pwx). This is because the light incident on the mold mark (19) / substrate mark (20) is diffracted in the X-axis direction by the mold mark (19) and the substrate mark (20), respectively. In addition, this is also the same for mold marks (19) / substrate marks (20) when the measurement direction is the same as the Y-axis (second direction) which is orthogonal to the X-axis of the pupil plane (1 or 2), and can explain diffracted light (5a, 5b, 5c, 5d).

[0040] Pattern edge light (6) is described with reference to FIG. 7. Pattern edge light (6) is diffracted light at each edge of the entire pattern of the diffraction grating (19b (19b'), 20b (20b')) of the mold mark (19) and the substrate mark (20). Note that at the edge portions of each small pattern element forming the diffraction grating (19b (19b'), 20b (20b')), diffracted light is not detected because the pitch is small. Pattern edge light at the diffraction grating (19b) of the mold mark (19) is described. Light incident on the entire edge of the diffraction grating (19b) is diffracted only in the direction of the axis orthogonal to the edge. This is because the entire edge of the diffraction grating (19b) is parallel to one of the X-axis and the Y-axis. For example, when light is incident on an edge in a direction parallel to the X-axis, the diffracted light becomes in a direction parallel to the Y-axis. On the other hand, when light is incident on an edge in a direction parallel to the Y-axis, the light is diffracted in a direction parallel to the X-axis. This is also the same for diffracted light from the diffracting grating (19b') of the mold mark (19) and the diffracting grating (20b, 20b') of the substrate mark (20). Accordingly, the pattern edge light (6) passes through the X-axis and its vicinity and the Y-axis and its vicinity on the pupil surface (2) of the detection system (21).

[0041] With reference to FIGS. 8A and 8B, an illumination aperture (27) and a detection aperture (26) for removing pattern edge light (6), which is unwanted light, will be described. In order to induce light parallel to the optical axis into the mold mark (19), it is advantageous to form a light intensity distribution at the exit of the pupil surface (1) of the illumination system (22) that has light intensity concentrated only at the intersection of the X-axis and Y-axis (i.e., the optical axis) and its vicinity. To this end, an illumination aperture (27) (pinhole plate) including an opening (pinhole) at the intersection of the X-axis and Y-axis may be placed on the pupil surface (1). By doing so, it becomes possible to induce light parallel to the optical axis of the light source (23) into the mold mark (19) (diffraction grating (19b, 19b')).

[0042] The diffracted light (4a to 4d, 5a to 5d) that forms a moiré pattern on the imaging surface of the image sensor (25) is incident on an area that is not on the X-axis and Y-axis of the pupil surface (2) of the detection system (21). Meanwhile, the pattern edge light (6) is incident on the X-axis and its vicinity and the Y-axis and its vicinity on the pupil surface (2) of the detection system (21). The pattern edge light (6) becomes noise light when measuring the relative position between the diffraction grating (19b (19b')) and the diffraction grating (20b (20b')) from the moiré pattern phase difference. To solve this, the pattern edge light (6) can be blocked by placing a detection aperture (26) including a light-blocking body (260) on the X-axis and its vicinity and the Y-axis and its vicinity on the pupil surface (2) of the detection system (21).

[0043] A light-blocking body (260) disposed on the pupil surface (2) of the detection system (21) may include a first light-blocking part (261) that crosses the optical axis of the detection system (21) in a direction parallel to the x-axis (third direction), and a second light-blocking part (262) that crosses the optical axis of the detection system (21) in a direction parallel to the y-axis (fourth direction). The light-blocking body (260) may further include a third light-blocking part (263) aligned with the optical axis. The third light-blocking part may have a circular shape. As described above, the direction parallel to the x-axis (third direction) is a direction conjugated to the direction parallel to the X-axis (first direction), and the direction parallel to the y-axis (fourth direction) is a direction conjugated to the direction parallel to the Y-axis (second direction). The illumination aperture (27) may be a pinhole plate including a pinhole having a diameter (d).

[0044] The pupil surface (2) of the detection system (21) includes a light-transmitting area (265) in an area where a light-blocking body (260) is not placed. Diffracted light from the mold mark (19) (19b, 19b') and substrate mark (20) (20b, 20b') illuminated by illumination light passes through the light-transmitting area (265), thereby forming optical information indicating the relative position between the mold (16) and the substrate (17) on the imaging surface of the image sensor (25). Among the light from the mold mark (19) (19b, 19b') and substrate mark (20) (20b, 20b') illuminated by illumination light, unnecessary light that does not contain optical information indicating the relative position can be blocked by the first light-blocking part (261) and the second light-blocking part (262).

[0045] When the diameter of the concentrated light intensity portion (i.e., pinhole) in the light intensity distribution (3) formed at the exit of the pupil surface (1) of the lighting system (22) is denoted as d, the width of the pattern edge light (6) in the pupil surface (2) of the detection system (21) is also d. Therefore, in order to block the pattern edge light (6), it is preferable that the width (D) of the first light-blocking portion (261) and the second light-blocking portion (262) of the detection aperture (26) be equal to or greater than d. The diffracted light (4a to 4d, 5a to 5d) for forming an image on the imaging surface of the image sensor (25) from the moiré pattern needs to be incident on an area other than the light-blocking body (260) in the pupil surface (2) of the detection system (21). For example, regarding the diffracted light (4a), it is preferable that the distance from the X-axis (|f·tanθwy|) and the distance from the Y-axis (|f·tan(θmx-θwx)|) at the pupil surface (2) of the detection system (21) be greater than the sum of half the width (D) of the light-shielding body (260) and the radius (r) of the diffracted light (4a). In this example, the width (D) of the light-shielding body (260) is the width in the X direction of the second light-shielding part (262) with respect to the X direction, and the width in the Y direction of the first light-shielding part (261). Expressing the condition as an equation, it is preferable that the width (D) of the light-shielding body (260) satisfy the following equation.

[0046] |f·tanθwy| - r ≥ D / 2 ≥ d / 2, and

[0047] |f·tan(θmx-θwx)| - r ≥ D / 2 ≥ d / 2

[0048] In this example, r is greater than d because the number of pitches of the mold mark (19) and the substrate mark (20) is finite. For example, in the case of diffracted light (5a), it is preferable that the width (D) of the light shield satisfies the following equation.

[0049] |f·tanθwx| - r ≥ D / 2 ≥ d / 2, and

[0050] |f·tan(θmy-θwy)| - r ≥ D / 2 ≥ d / 2

[0051] Note that the mark that generates the diffracted light (5a) is a mark whose measurement direction is the Y direction.

[0052] With reference to FIGS. 9a and 9b, the influence of the presence or absence of pattern edge light (6) on the moiré pattern phase difference measurement will be explained. As shown in an arbitrary cross-section (31) of the measurement direction of the moiré pattern containing pattern edge light (6), when pattern edge light (6) is present in each edge portion of the moiré pattern, this becomes a noise component, and thereby the measurement precision of the relative phase deteriorates. The closer the moiré pattern is to the pattern edge light (6), the greater the influence of the noise component. Therefore, it is difficult to reduce the size of the alignment mark. On the other hand, as shown in an arbitrary cross-section (32) of the measurement direction of the moiré pattern where the pattern edge light (6) is removed, when only the moiré signal is present, the measurement precision of the relative phase is improved. In addition, it is expected that the measurement precision of the relative phase will also be improved by reducing the shot noise of the image sensor (25).

[0053] Next, a method for manufacturing an article using an imprint device represented by the above-described embodiment will be described. The article may be, for example, a semiconductor device, a display device, a MEMS, etc. The method for manufacturing an article may include a transfer step of transferring a pattern of a plate onto a substrate using a lithography device or an imprint device, and a processing step of processing the substrate so that an article is obtained from the substrate that has undergone the transfer step. The transfer step may include, for example, a contact step of bringing the imprint material (18) on the shot area of ​​the substrate (17) and the mold (16) into contact with each other. Additionally, the transfer step may include a measurement step of measuring the relative position between the shot area (or substrate mark) of the substrate (17) and the mold (16). Additionally, the transfer step may include an alignment step of aligning the shot area of ​​the substrate (17) and the mold (16) based on the result of the measurement step. Additionally, the transfer step may include a curing step of curing the imprint material (18) on the substrate (17) and a separation step of separating the imprint material (18) from the mold (16). Accordingly, a pattern consisting of a cured imprint material (18) is formed or transferred onto a substrate (17). The processing steps may include, for example, etching, resist stripping, dicing, bonding, and packaging.

[0054] The pattern of a cured product formed using an imprint device is used permanently on at least a part of various articles or temporarily when manufacturing various articles. Articles include electrical circuit elements, optical elements, MEMS, recording elements, sensors, molds, etc. Examples of electrical circuit elements include volatile or non-volatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, and semiconductor devices such as LSI, CCD, image sensors, and FPGA. An example of a mold is an imprint mold.

[0055] The pattern of the cured product is used as is as a component of at least part of the aforementioned article or is used temporarily as a resist mask. After etching or ion implantation is performed during the substrate processing step, the resist mask is removed.

[0056] Next, a method for manufacturing an article is described 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. As shown in FIG. 10a, 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.

[0057] As shown in FIG. 10b, the side of the imprint mold (4z) having a concave-convex pattern is positioned toward the imprint material (3z) on the substrate. As shown in FIG. 10c, the substrate (1z) to which the imprint material (3z) is applied is brought into contact with the mold (4z), and pressure is applied. The imprint material (3z) fills the gap between the mold (4z) and the workpiece (2z). 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.

[0058] As shown in FIG. 10d, after curing the imprint material (3z), 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).

[0059] As shown in FIG. 10e, when etching is performed using the pattern of the cured material as an etching mask, the portion of the surface of the workpiece (2z) where the cured material does not exist or remains thinly is removed, and a groove (5z) is formed. As shown in FIG. 10f, when the pattern of the cured material is removed, an article with 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 insulating film, i.e., a constituent member of an article, which is included in, for example, a semiconductor device.

[0060] 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 relative position between a first mark and a second mark provided respectively on a first object and a second object arranged to overlap each other, and a lighting system configured to illuminate the first mark and the second mark with lighting light, wherein the lighting system includes a pinhole plate arranged on the pupil surface of the lighting system, and the lighting light is light that has passed through the pinhole of the pinhole plate; A detection device comprising an image sensor and a first mark and a second mark, wherein the detection device comprises a detection system configured to form an image on the imaging surface of the image sensor from diffracted light from the first mark and the second mark illuminated by the illumination system, wherein the first mark and the second mark are configured to form optical information indicating the relative position in a first direction or a second direction orthogonal to the first direction on the imaging surface, wherein the illumination light is light that passes only through the optical axis of the illumination system and the vicinity of the optical axis on the pupil surface of the illumination system, and wherein a light-blocking body is provided on the pupil surface of the detection system, the light-blocking body comprising a first light-blocking part crossing the optical axis of the detection system in a direction parallel to a third direction and a second light-blocking part crossing the optical axis of the detection system in a direction parallel to a fourth direction, wherein the third direction is a direction conjugated to the first direction and the fourth direction is a direction conjugated to the second direction. Claim 2 delete Claim 3 A detection device according to claim 1, wherein the width of the first light-blocking part in the fourth direction and the width of the second light-blocking part in the third direction are not smaller than the diameter of the pinhole. Claim 4 In claim 1, the lighting system and the detection system share a prism, the pupil surface of the lighting system is positioned between a light source and the prism, and the lighting light is reflected by the prism to illuminate the first mark and the second mark. Claim 5 In paragraph 4, the diffracted light from the first mark and the second mark passes through the prism and is incident on the imaging surface, and the pupil surface of the detection system is a detection device disposed between the prism and the imaging surface. Claim 6 A detection device according to claim 1, wherein the first light-blocking part extends over the diameter in the third direction of the pupil surface of the detection system, and the second light-blocking part extends over the diameter in the fourth direction of the pupil surface of the detection system. Claim 7 A detection device according to claim 1, wherein the pupil surface of the detection system includes a light-transmitting region in an area where the light-blocking body is not disposed, and the diffracted light from the first mark and the second mark illuminated by the illumination light passes through the light-transmitting region to form the optical information indicating the relative position on the imaging surface. Claim 8 A detection device according to claim 7, wherein the first diffracted light from the first mark and the second mark illuminated by the illumination light passes through the light transmission region to form the optical information indicating the relative position on the imaging surface. Claim 9 In claim 1, the detection device further comprises a third light-blocking member that is aligned with the optical axis of the detection system. Claim 10 In paragraph 1, the detection device wherein the illumination light is unpolarized light. Claim 11 A detection device according to claim 1, wherein among the light from the first mark and the second mark illuminated by the illumination light, unnecessary light that does not include optical information indicating the relative position is blocked by both the first light-blocking part and the second light-blocking part. Claim 12 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 11, wherein the lithography device is configured to align the disc as a first object provided with a first mark and the substrate as a second object provided with a second mark based on the output from the detection device. Claim 13 In Clause 12, the lithography device is a lithography device formed as an imprint device. Claim 14 A method for manufacturing an article, comprising: a transfer step of transferring a pattern of a plate onto a substrate using a lithography device specified in claim 13; and a processing step of processing the substrate to obtain an article from the substrate that has undergone the transfer step.

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