JP2012114279A - Focusing device, exposure device, and device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focusing device capable of focusing accurately even when an area having a step exists against a target area for focusing in a periphery of the target area.SOLUTION: A focusing device 4 of an embodiment is a focusing device to focus a focal point of an optical system 3 to a focusing target plane having a step against a reference plane Pa and comprises a controller 5 to obtain a focusing condition in which the focal point of the optical system 3 coincides the focusing target plane by using a condition in which the focal point of the optical system 3 coincides the reference plane and the information of the step.

Description

  The present invention relates to a focusing apparatus, an exposure apparatus, and a device manufacturing method.

  An exposure apparatus is used for pattern formation when manufacturing various devices (see, for example, Patent Document 1). The exposure apparatus includes, for example, a substrate stage, a projection optical system, and a focusing device. The substrate stage holds a substrate that is an object to be exposed and manages the position of the substrate with respect to the projection optical system. For example, the focusing device detects the detection light applied to the substrate and focuses the projection optical system on the surface of the substrate.

JP 2004-303951 A

By the way, when manufacturing a device such as a MEMS, for example, a structure may be formed inside the convex portion or the concave portion. When exposing the top of the convex part or the bottom of the concave part, if the projection optical system is focused on the exposure target area, the spot of the detection light used for focusing may protrude beyond the target area. . Then, in addition to the detection light that has passed through the target area, the detection light that has passed through a surface that forms a step with respect to the target area may also be detected.
The present invention has been made in view of the above-described circumstances, and one of the objects is to enable accurate focusing even when there is a region that forms a step with the target region around the target region to be focused. To do.

  A focusing device according to a first aspect of the present invention is a focusing device that focuses an optical system on a focusing target surface that is stepped from a reference surface, and the optical system is focused on the reference surface. And a control unit that obtains an in-focus condition in which the focal point of the optical system matches the in-focus target surface using the information on the step.

  An exposure apparatus according to the second aspect of the present invention includes the focusing apparatus according to the aspect of the present invention.

  A device manufacturing method according to a third aspect of the present invention includes exposing a substrate using the exposure apparatus according to the aspect of the present invention, and developing the exposed substrate.

  According to the present invention, it is possible to focus accurately even when there is a region that is stepped from the target region around the target region to be focused.

It is a schematic block diagram which shows an example of the exposure apparatus of this embodiment. It is a figure which shows an example of the structure on the board | substrate in this embodiment. It is a top view which shows the example of the slit image in this embodiment. It is a top view which shows the example of the slit image in this embodiment. It is a figure which shows an example of the device manufacturing method which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The technical scope of the present invention is not limited to the following embodiments. Various modifications are possible without departing from the gist of the present invention.

FIG. 1 is a schematic block diagram that shows an example of the exposure apparatus of this embodiment.
The exposure apparatus EX of the present example includes a substrate stage 1, a pattern generation unit 2, a projection optical system 3, a focusing device 4 to which the present invention is applied, and a control unit 5. The focusing device 4 of this example can focus the projection optical system 3 on the exposure surface by TTL type phase difference autofocus (hereinafter abbreviated as AF). The control unit 5 controls the operation of each unit of the exposure apparatus EX and includes a control unit of the focusing device 4. Note that the control unit of the focusing device 4 may be provided separately from the control unit 5 and may control the position of the substrate stage 1 indirectly or directly via the control unit 5.

  In the following description, the positional relationships of various components will be described based on the XYZ orthogonal coordinate system shown in FIG. In this XYZ orthogonal coordinate system, the Z-axis direction is a direction parallel to the optical axis on the light emission side of the projection optical system 3, and the X-axis direction and the Y-axis direction are orthogonal to the optical axis on the light emission side of the projection optical system 3. The directions are orthogonal to each other in the plane to be performed. For example, the X-axis direction and the Y-axis direction are set to the horizontal direction, and the Z-axis direction is set to the vertical direction.

  The exposure apparatus EX of this example is a maskless type exposure apparatus. The exposure apparatus EX is used for manufacturing a device such as a MEMS. The substrate P in this example is a device manufacturing substrate. The substrate P includes a substrate body P0. The substrate body P0 is, for example, a quartz substrate, a glass substrate, a silicon-containing semiconductor substrate, or a substrate obtained by bonding two or more kinds of substrates having different materials. Here, for convenience of explanation, one surface of the substrate P is referred to as a front surface Pa, and the other surface is referred to as a back surface Pb. A structure P1 is formed on the surface Pa of the substrate P. The exposure apparatus EX can expose this area in a state where the projection optical system 3 is focused on an area that is inside the structure P1.

  The substrate P may include a film pattern formed on the substrate body P0. This film pattern is, for example, a component that constitutes a part of the device. Specific examples of the film pattern include a conductive film pattern serving as an electrode and wiring, a semiconductor film pattern constituting a part of the switching element, an insulating film pattern serving as a passivation film, and the like. The substrate P may include a photosensitive film (photoresist film) formed on the substrate body P0. The substrate P includes, for example, an antireflection film that prevents reflection of the exposure light EL, a protective film (topcoat film) that protects the photosensitive film, and the like as a film that functions in the manufacturing process of the device or after the manufacturing. Sometimes.

  The exposure apparatus EX generally operates as follows. The substrate stage 1 is movable while holding the substrate P to be exposed. The control unit 5 manages the position of the substrate stage 1 and substantially manages the relative position between the projection region of the projection optical system 3 and the substrate P. The focusing device 4 focuses the projection optical system 3 on the exposure target area. The pattern generation unit 2 is controlled by the control unit 5 to generate a pattern image. The projection optical system 3 projects the pattern image generated by the pattern generation unit 2 onto the substrate P.

Next, components of the exposure apparatus EX will be described in detail.
The substrate stage 1 detachably holds the substrate P by, for example, reduced-pressure adsorption or electrostatic adsorption. The substrate P is held on the upper surface 1a of the substrate stage 1 so that the normal direction of the front surface Pa and the back surface Pb is substantially parallel to the Z-axis direction. The substrate stage 1 can move the substrate P in six directions including an X-axis direction, a Y-axis direction, a Z-axis direction, a rotation direction around the X-axis, a rotation direction around the Y-axis, and a rotation direction around the Z-axis. The substrate stage 1 of this example includes an XY stage that can move the substrate P in the X-axis direction and the Y-axis direction, and a Z stage that can move the substrate P in the Z-axis direction.

  The pattern generation unit 2 includes an exposure light source 6, a collector lens 7, an image forming unit 8, and an objective lens (second objective lens) 9. The exposure light EL emitted from the exposure light source 6 is collimated through the collector lens 7 and enters the image forming unit 8. The image forming unit 8 forms an image of a pattern using the exposure light EL. The exposure light EL emitted from the image forming unit 8 is incident on the objective lens 9 as light indicating a pattern image.

The exposure light EL is, for example, far ultraviolet light (DUV light) such as bright lines (g-line, h-line, i-line) and KrF excimer laser light (wavelength 248 nm) emitted from a mercury lamp, ArF excimer laser light (wavelength 193 nm) , And vacuum ultraviolet light (VUV light) such as F ₂ laser light (wavelength 157 nm). The configuration of the exposure light source 6 is appropriately selected according to the wavelength of the exposure light EL or the like. The controller 5 controls operations such as turning on and off the exposure light source 6.

  The image forming unit 8 can form an image of a pattern to be projected as an image, for example. The image forming unit 8 of this example includes a digital mirror device (DMD). The DMD has a plurality of pixels arranged two-dimensionally. Each pixel of the DMD includes a micromirror, and reflects the divided light beam of the exposure light EL that has entered the pixel. The reflection surface of the micromirror can be variably controlled with respect to the traveling direction of the incident exposure light EL. As described above, the image forming unit 8 can control the traveling direction of the divided light beam reflected by each pixel for each pixel, and can form a pattern image. The control unit 5 supplies data indicating a pattern image formed by the image forming unit 8 to the image forming unit 8 and controls the operation of the image forming unit 8.

  Note that a self-luminous panel may be used as the image forming unit 8. This self-luminous panel includes a plurality of light-emitting elements arranged two-dimensionally. Each light emitting element is constituted by a laser diode or a light emitting diode. Each light emitting element can be turned on / off for each light emitting element. A self-luminous panel can emit light indicating each pixel from each light-emitting element to form a pattern image.

  A wavelength selection mirror 10 is disposed at a position where the exposure light EL emitted from the objective lens 9 is incident. The wavelength selection mirror 10 is configured by, for example, a dichroic mirror. The wavelength selection mirror 10 of this example has a characteristic that the exposure light EL is reflected and the detection light SL described later passes.

  The exposure light EL emitted from the objective lens 9 and reflected by the wavelength selection mirror 10 is reflected by the wavelength selection mirror 10 and then enters the projection optical system 3. The projection optical system 3 includes one or more optical components (first objective lens) such as a lens. An image of the pattern indicated by the exposure light EL is projected onto a projection area on the substrate P. The projection area includes an area where a pattern image can be projected by the projection optical system 3.

  The focusing device 4 includes an AF light source 11, a collector lens 12, a slit 13, an objective lens (second objective lens) 14, an aperture 15, a spectral component 16, an objective lens (second objective lens) 17, a reflection mirror 18, and a cylindrical. A lens 19, a detection unit 20, and a control unit are included. As described above, the control unit of the focusing device 4 of this example is included in the control unit 5 of the exposure apparatus EX.

  The focusing device 4 of this example includes a position detection system. The position detection system includes an objective lens (second objective lens) 22 and a detection unit 23, and detects an alignment mark or the like provided on the substrate P. The detection result of the detection unit 23 is output to the control unit 5 and used for position management of the substrate stage 1 and the like. In this example, the detection light SL emitted from the AF light source 11 is also used to detect an alignment mark. As described below, the detection light SL passes through the projection optical system 3 and the wavelength selection mirror 10 from the substrate P and enters the spectroscopic component 21. The detection light SL that has passed through the spectral component 21 passes through the objective lens 22 and enters the detection unit 23. The detection unit 23 is constituted by, for example, a CCD camera or the like, and can detect the intensity distribution of the incident detection light SL. An alignment mark is detected based on the detection result of the intensity distribution of the detection light SL.

  For example, the AF light source 11 emits light having a wavelength different from that of the exposure light EL as detection light SL. The AF light source 11 of this example includes a light emitting element that emits infrared light as the detection light SL. The detection light SL emitted from the AF light source 11 passes through the collector lens 12 and enters the slit 13. The slit 13 functions as a field stop, and adjusts the spot shape of the detection light SL that has passed through the slit 13. The detection light SL that has passed through the slit 13 passes through the objective lens 14 and then enters the diaphragm 15.

  The diaphragm 15 in this example is disposed on the pupil plane of the optical system closer to the AF light source 11 than the diaphragm 15. The stop 15 functions as an aperture stop, and shields the detection light SL corresponding to almost half of the spots formed on the pupil plane by the detection light SL emitted from the objective lens 14. The diaphragm 15 can switch a light shielding range among the spots, and can switch an angle component passing through the diaphragm 15 in the detection light SL. The detection light SL that has passed through the diaphragm 15 enters the spectral component 16.

  The spectroscopic component 16 splits the incident detection light SL. The spectral component 16 is configured by an optical component such as a half mirror or a wavelength selection mirror. The spectral component 16 is set to a value selected from a range in which the reflectance with respect to the detection light SL is greater than 0 and less than 1. A part of the detection light SL incident on the spectroscopic component 16 is reflected by the spectroscopic component 16, and the other part passes through the spectroscopic component 16. The detection light SL reflected by the spectral component 16 passes through the wavelength selection mirror 10 and then enters the spectral component 21.

  Similar to the spectral component 16, the spectral component 21 splits the incident detection light SL. The detection light SL reflected by the spectroscopic component 21 is incident on the substrate P through the wavelength selection mirror 10 and the projection optical system 3. At least a part of the detection light SL incident on the substrate P is reflected and folded by the substrate P, passes through the projection optical system 3 and the wavelength selection mirror 10, and enters the spectral component 21 again.

  At least a part of the detection light SL incident on the spectral component 21 via the substrate P is reflected by the spectral component 16 after being reflected by the spectral component 21. The detection light SL reflected by the spectral component 16 passes through the objective lens 17 and is then reflected by the reflection mirror 18. The detection light SL reflected by the reflection mirror 18 passes through the cylindrical lens 19 and enters the detection unit 20. The detection light SL passing through the cylindrical lens 19 is refracted in a plane parallel to the XZ plane, is hardly refracted in a plane parallel to the XY plane, and is condensed toward a line substantially parallel to the Y-axis direction.

  The detection unit 20 can detect the intensity distribution of the detection light SL incident on the detection unit 20. The detection unit 20 is configured by, for example, a CCD line sensor. This CCD line sensor includes a plurality of pixels arranged in a region substantially parallel to the YZ plane and extending in the Y-axis direction. Each pixel of the CCD camera includes a light receiving element such as a photodiode and a switching element such as a thin film transistor. When the detection light SL is incident on the light receiving element, a charge is generated in the light receiving element. The switching element switches reading of electric charges generated in the light receiving element.

  Based on the detection result of the detection unit 20, an image of the slit 13 by the detection light SL reflected by the substrate P is detected. When the angle component of the detection light SL passing through the diaphragm 15 is switched, the position of the image detected by the detection unit 20 is switched. The interval between images before and after switching (hereinafter referred to as image interval) varies depending on the relationship between the focal position of the projection optical system 3 and the position of the substrate P. For example, the surface Pa of the substrate P is set as the focus target surface, and the image interval in a state where the projection optical system 3 is focused on the focus target surface (focus state) is set as the reference value. In a state where the focal point of the projection optical system 3 is positioned on the + Z side with respect to the focusing target surface (hereinafter referred to as a front pin), the image interval is narrower than the reference value. In a state where the focal point of the projection optical system 3 is located on the −Z side with respect to the focusing target surface (hereinafter referred to as a rear pin), the image interval is wider than the reference value.

  Thus, based on the detection result of the detection unit 20, it is determined whether or not the focus state is achieved, and it is known whether the focus is shifted from the focus state to the front pin side or the rear pin side. Is possible. The image interval is a value based on the intensity of light (detection light) that has passed through the substrate P, which is an object to be focused, and can be used as a determination parameter value used for determining the focus state. The detection result of the detection unit 20 is output to the control unit (here, the control unit 5) of the focusing device 4. The control unit 5 controls the position of the substrate stage 1 based on the detection result of the detection unit 20 so as to be in focus. That is, the control unit 5 of the present example adjusts the distance (focusing condition) from the projection optical system 3 to the focusing target surface by controlling the position of the substrate stage 1.

  The control unit 5 of this example is configured by a computer having a calculation unit such as a CPU and a storage unit such as a memory. This computer, when performing the focusing process and the exposure process described later in the exposure apparatus EX, controls each part of the exposure apparatus EX according to a program that executes control of each part that operates in the focusing process and control of each part that operates in the exposure process. To control. Note that the control unit 5 may include a logic circuit such as an ASIC. The control unit 5 may be configured such that the logic circuit and the computer cooperate to control each unit of the exposure apparatus EX.

FIG. 2A is a plan view showing an example of a structure on a substrate in the present embodiment, and FIG. 2B is a cross-sectional view taken along the line BB ′ in FIG.
The structure P1 of this example includes a concave portion that is concave toward the outside of the substrate P. The structure P1 may include a convex portion that is convex toward the outside of the substrate P. The bottom surface Pc of the recess forms a step d1 with respect to the surface Pa of the substrate P. The thickness d0 of the substrate P is, for example, not less than 0.1 mm and not more than 10 mm. The step d1 is not less than 1/10 and not more than 9/10 of the thickness d0, for example. The external shape of the recessed part of the structure P1 of this example is substantially square. The outer shape of the concave portion of the structure P1 is appropriately selected from a polygon, an ellipse (including a circle), a shape with rounded corners of a polygon, a shape with a free curve as an outline, and the like. The inner dimension (caliber) of the recess is, for example, 10 mm or less, and may be 2 mm or less or 1 mm or less. The inner dimension of the recess may be defined by the length of the short side of the rectangle, assuming a minimum rectangle that can accommodate the outline of the structure.

  Here, it is assumed that an image of the slit 13 is formed on the bottom surface Pc, and AF is applied to the bottom surface Pc based on the detection result of this image. In this case, if the image of the slit 13 extends over the surface Pa and the bottom surface Pc, the focus of the projection optical system 3 may be shifted from the bottom surface Pc due to the influence of the detection result of the image on the surface Pa. . Further, if an image of the slit 13 is formed so as to be within the bottom surface Pc, the magnification of the projection optical system 3 or the magnification of the objective lens 14 is restricted, or the image formation position of the slit 13 and the bottom surface Pc are increased. It may be necessary to align to accuracy.

  The focusing device 4 of this example is used for focusing by using the condition that the projection optical system 3 is focused on the reference plane and information on the level difference between the reference plane and the focusing target plane (exposure target plane). The projection optical system 3 can be focused on the focus target surface without irradiating the focus target surface with light. The exposure apparatus EX of this example can expose at least a part of the focus target surface with exposure light in a state where the focus target surface is in focus.

  Next, an example of the exposure method in this embodiment will be described. In this example, the focusing process is performed before the exposure process. In the focusing process of this example, a step between the focusing target surface and the reference surface in the structure P1 is obtained (measurement step), and the projection optical system 3 is focused on the reference surface (temporary focusing step). Then, based on the step, the focus target surface is moved to the position of the reference surface when the reference surface is focused (correction step). In the exposure apparatus EX of this example, the control unit 5 controls each unit to perform focusing processing and exposure processing. The control unit 5 of this example controls each part of the exposure apparatus EX according to a program for executing control of each part operating in each step when performing the above-described measurement step, provisional focusing step, and correction step.

  In this example, the focusing target surface is the exposure target surface (bottom surface Pc), and the reference surface is the surface Pa of the substrate P. The reference plane is selected from a plane including a plane on which the entire image of the slit 13 can be projected, for example. Since the reference plane (surface Pa) is selected from a region where the entire image of the slit 13 can be projected, it can be expected to be focused on the surface Pa with high accuracy. The reference surface may be the upper surface 1a of the substrate stage 1 or may be the upper surface of another stage that can be disposed facing the projection optical system 3. The reference plane may be a surface of a dummy substrate different from the substrate P to be exposed.

  In the measurement step of this example, a measurement device capable of measuring the level difference between the surface Pa and the bottom surface Pc is used. This measuring apparatus includes, for example, a microscope, and is disposed on a transport path through which, for example, the substrate P is transported to the substrate stage 1. The control part 5 of this example controls this measuring apparatus. Information indicating the level difference between the front surface Pa and the bottom surface Pc measured by the measuring device is stored in the storage unit of the control unit 5. In this example, the measurement step is performed for each substrate P. Note that a measurement step may be performed on one of the plurality of substrates P, and the obtained measurement value may be used as a value common to the plurality of substrates P.

  Note that the measuring apparatus may be provided on the substrate stage 1. Further, the step between the surface Pa and the bottom surface Pc may be measured using the focusing device 4. In order to measure the level difference using the focusing device 4, for example, at least one of the magnification of the projection optical system 3 and the magnification of the objective lens 14 is set to a magnification at the time of exposure so that the image of the slit 13 can be accommodated in the structure P1. By changing from (second magnification), autofocus is applied to the front surface Pa and the bottom surface Pc, respectively. For example, the magnification may be changed to a magnification (first magnification) higher than the magnification at the time of exposure so that the image of the slit 13 fits in the structure P1. Then, the step is obtained by obtaining a difference between the Z coordinate of the substrate stage 1 when focused on the front surface Pa and the Z coordinate of the substrate stage 1 when focused on the bottom surface Pc. Can do.

Further, the exposure apparatus EX includes a substrate stage and a measurement stage as disclosed in, for example, US Pat. No. 6,897,963 and European Patent Application Publication No. 1713113, and a part of the measurement apparatus. Alternatively, all may be included in the measurement stage.
In addition, instead of measuring the step, the step design value (step information) is stored in the storage unit of the control unit 5, for example, and the control unit 5 reads out the information indicating the step from the storage unit. The structure which calculates | requires may be sufficient.

  FIG. 3A is a plan view schematically showing an example of a slit image projected on the surface of the substrate when the position of the substrate stage is controlled in the provisional focusing step. In the temporary focusing step of this example, the control unit 5 controls the position of the substrate stage 1 so as to focus on the surface Pa based on the detection result of the detection unit 20.

  In this example, an image of the slit 13 is projected at each projection position for a plurality of different projection positions on the surface Pa, and this image is focused on the surface Pa based on the detection result detected by the detection unit 20. The Z coordinate of the substrate stage 1 is obtained for each projection position. Then, using the plurality of results obtained as the Z coordinate of the substrate stage 1 when focused on the surface Pa, the surface Pa is located at the position of the structure P1 when the surface Pa exists at the position of the structure P1. An estimated value of the Z coordinate of the substrate stage 1 when focusing on Pa is obtained by interpolation or the like.

  Specifically, the image of the slit 13 is projected onto the surface Pa around the structure P1, and the detection result of the image 13A detected by the detection unit 20 is based on the detection result of the substrate stage 1 when focused on the surface Pa. Find the Z coordinate. Similar to the case where the image 13B of the slit 13 is projected to the position opposite to the position where the image 13A is projected, the Z coordinate of the substrate stage 1 at the time of focusing is obtained. Ask.

  Further, regarding a line intersecting with a line connecting the projection position of the image 13A and the projection position of the image 13B, the substrate stage at the time of focusing when the image 13C is projected onto one of a pair of projection positions sandwiching the structure P1 on this line. 1 and the Z coordinate of the substrate stage 1 at the time of focusing when the image 13D is projected onto the other. As described above, the estimated value is obtained by interpolating using the Z coordinate of the substrate stage 1 at the time of focusing when the images 13A to 13D are projected. In this example, an estimated value is obtained for each substrate P.

  The estimated value obtained by performing a temporary focusing step on one of the plurality of substrates P may be used as a common value for the plurality of substrates P. That is, the Z coordinate of the substrate stage 1 when focused on the surface Pa is obtained based on the estimated value obtained from one substrate P, and the surface Pa of another substrate P is obtained using this Z coordinate. You may set the Z coordinate of the substrate stage 1 when making it focus.

  In the correction step of this example, the control unit 5 controls the position of the substrate stage 1 based on the step between the front surface Pa and the bottom surface Pc so that the projection optical system 3 is focused on the bottom surface Pc. The control unit 5 in this example reads information indicating the level difference between the front surface Pa and the bottom surface Pc from the storage unit. The control unit 5 of this example controls the position of the substrate stage 1 so that the substrate stage 1 approaches the projection optical system 3 by the above step from the state where the projection optical system 3 is focused on the surface Pa. That is, the control unit 5 of this example has a value corresponding to the distance (focusing condition) from the projection optical system 3 to the focusing target surface when the projection optical system 3 is focused on the focusing target surface (bottom surface Pc). As described above, the Z coordinate of the substrate stage 1 is obtained using the measured value of the step. In addition, if the Z coordinate of the substrate stage 1 when the image of the slit 13 is projected onto a plurality of projection positions around the structure P1, unevenness on the surface of the substrate P can be taken into consideration, and the bottom surface Pc. Can be expected to be focused with high accuracy.

  In order to focus the projection optical system 3 on the top surface of the structure P1 that is a convex portion, the step between the top surface and the surface Pa is changed from the state in which the projection optical system 3 is focused on the surface Pa. The position of the substrate stage 1 may be controlled so that the substrate stage 1 moves away from the projection optical system 3 only.

  As described above, according to the focusing device 4, even when there is a region (front surface Pa) that forms a step with the target region around the target region (bottom surface Pc) to be focused, it is possible to focus accurately. The control unit 5 of this example controls the pattern generation unit 2 while being focused on the bottom surface Pc that is the exposure target surface. In this example, the pattern generation unit 2 forms an image of the pattern to be exposed, and the projection optical system 3 projects this image onto the bottom surface Pc, and the exposure process is performed.

FIGS. 3B, 4A, and 4B are plan views showing other examples of slit images in the present embodiment.
In Modification 1 shown in FIG. 3B, the outer shapes (spot shapes) of the images 13A to 13D of the slit 13 are substantially circular.

  In the modification 2 shown to Fig.4 (a), the external shape (spot shape) of the images 13A-13D of the slit 13 is substantially square. In this example, the position where the image 13A is projected and the position where the image 13B is projected are aligned in the diagonal direction of the square. Similarly, the projected positions of the images 13C and 13D are aligned in the diagonal direction of the square.

  In Modification 3 shown in FIG. 4B, the substrate P is provided with a plurality of structures P1. The images 13A to 13D of the slit 13 are respectively projected between the structure P1 and another structure P1 adjacent to the structure P1. In this example, the plurality of structures P1 are all in the same shape. In this example, after performing the temporary focusing step by sequentially projecting the images 13A to 13D of the slit 13 around one of the plurality of structures P1, each of the regions inside the plurality of structures P1 is performed. To perform exposure processing. In this exposure process, each structure P1 may be exposed in one shot, or two or more structures P1 may be exposed in one shot at a time.

  In the above-described embodiment and each modified example, the slit image is sequentially projected on the four places around the structure P1, but the projection area of the slit image may be one, two, or three. The number may be 5 or more.

  In the above embodiment, the distance from the projection optical system 3 to the substrate stage 1 is adjusted as a focusing condition by changing the Z coordinate of the substrate stage 1, but the Z coordinate of the projection optical system 3 is changed. Including adjustment, the distance from the projection optical system 3 to the substrate stage 1 may be adjusted. Further, information indicating the boundary between the reference surface (surface Pa) and the focus target surface (bottom surface Pc) may be used as the step information. For example, the magnification (focusing condition) of the projection optical system 3 is adjusted so that the spot of the detection light SL falls within the area surrounded by the boundary, and AF is performed in a state where the spot of the detection light SL falls on the focus target surface. You may spend it.

  FIG. 5 is a diagram illustrating an example of a device manufacturing method according to the present embodiment. In this example, in step 201, function / performance design of a device such as a liquid crystal panel is performed. In step 202, a mask (reticle) is fabricated based on the device design. When a device is manufactured using a maskless exposure apparatus, in step 202, the pattern shape is registered in a storage device inside or outside the control unit, for example. In step 203, a substrate which is a base material of the device is prepared. In step 204, a film pattern such as a conductive film pattern, an insulating film pattern, or a semiconductor film pattern constituting the device is formed on the substrate. Step 204 includes forming a film on the substrate, forming a resist pattern on the film, and etching the film using the resist pattern as a mask. In order to form a resist pattern, a resist film is formed and, according to the above-described embodiment, the substrate is exposed to exposure light, and a pattern image corresponding to the film pattern to be formed is projected onto the resist film on the substrate. And developing the exposed resist film. In step 205, according to the device to be manufactured, for example, the substrate is diced, a pair of substrates are bonded, a liquid crystal layer is formed between the pair of substrates, and the device is assembled. In step 206, the device is subjected to post-processing such as inspection. A device can be manufactured as described above.

In addition to the exposure apparatus, the present invention is applicable to a processing apparatus that irradiates a processing object with light via an optical system. An example of such a processing apparatus is a laser processing apparatus.
In the above embodiment, the TTL type phase difference type AF is described as an example. However, the present invention is also applicable to a TTL type contrast type AF, an oblique incidence type phase difference type AF, and the like. In the contrast method, in-focus determination is performed based on the contrast ratio inside and outside the spot formed on the focusing target surface by the light used for focusing (detection light SL), the dimensional change of the spot, and the like.

  In addition to the maskless type exposure apparatus, the present invention includes a step-and-scan type scanning exposure apparatus (scanning stepper) for scanning and exposing a mask pattern by synchronously moving the mask and the substrate, a mask, The present invention can also be applied to a step-and-repeat projection exposure apparatus (stepper) in which a mask pattern is collectively exposed while the substrate is stationary, and the substrate is sequentially moved stepwise. Further, in the step-and-repeat exposure, after the reduced image of the first pattern is transferred onto the substrate using the projection optical system while the first pattern and the substrate are substantially stationary, the second pattern and the substrate are transferred. May be exposed on the substrate in a lump by partially overlapping the first pattern with the projection optical system (stitch type lump exposure apparatus). The stitch-type exposure apparatus can also be applied to a step-and-stitch type exposure apparatus that partially transfers at least two patterns on a substrate and moves the substrate sequentially.

  The present invention, for example, as disclosed in US Pat. No. 6,611,316, combines two pattern images on a substrate via a projection optical system, and one shot on the substrate by a single scanning exposure. The present invention can be applied to an exposure apparatus that performs double exposure of a region almost simultaneously. The present invention can also be applied to proximity type exposure apparatuses, mirror projection aligners, and the like.

  The present invention can also be applied to an exposure apparatus provided with a plurality of substrate stages and measurement stages.

  The present invention includes an exposure apparatus for manufacturing a semiconductor element that exposes a semiconductor element pattern on a substrate, an exposure apparatus for manufacturing a liquid crystal display element or a display, a thin film magnetic head, an image sensor (CCD), a micromachine, a MEMS, a DNA chip, Alternatively, it can be widely applied to an exposure apparatus for manufacturing a reticle or a mask.

  In the present invention, the position information of each stage can be measured using an interferometer system including a laser interferometer, and the measurement result can be used for managing the position of the substrate. In addition to the interferometer system including the laser interferometer, for example, an encoder system that detects a scale (diffraction grating) provided on the substrate stage may be used.

  The present invention relates to an exposure apparatus (lithography system) that exposes a line and space pattern on a substrate by forming interference fringes on the substrate as disclosed in, for example, WO 2001/035168. Can be applied to.

  The exposure apparatus EX of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  The requirements of the above-described embodiments and modifications can be combined as appropriate. Some components may not be used. In addition, as long as permitted by law, the disclosure of all published publications and US patents related to the exposure apparatus and the like cited in the above-described embodiments and modifications are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 ... Substrate stage (stage), 2 ... Pattern generation part,
3 ... projection optical system (optical system), 4 ... focusing device, 5 ... control unit, d1 ... step,
EL ... exposure light, EX ... exposure device, P ... substrate (object),
Pa ... surface (reference surface), Pc ... bottom surface (focus target surface, exposure target surface),
SL: Detection light (light)

Claims (8)

A focusing device that focuses the optical system on a focusing target surface that forms a step with a reference surface,
An in-focus device comprising: a control unit that obtains an in-focus condition in which the focal point of the optical system is in focus with the in-focus target surface using information on the condition that the focal point of the optical system is in alignment with the reference plane and the step. The focusing condition includes a distance from the optical system to the focusing target surface,
The focusing device according to claim 1, wherein the control unit adjusts a distance from the optical system to the reference surface when the optical system is focused on the reference surface by the step. The step information includes information indicating a boundary between the focusing target surface and the reference surface, and the focusing condition includes a magnification of the optical system,
The control unit uses the information indicating the boundary so that the spot of light irradiated on the focusing target surface falls within the focusing target surface when searching for the focusing condition. The focusing device according to claim 1, wherein the focusing device is adjusted.   The focusing apparatus according to claim 1, wherein the reference plane is set around the focusing target surface.   The focusing device according to any one of claims 1 to 4, wherein the control unit obtains the focusing condition using a measurement value of the step.   An exposure apparatus comprising the focusing device according to any one of claims 1 to 5.   The control unit obtains the step by comparing the focusing condition with the focusing condition when the optical system is at the first magnification, and the optical system is based on the first magnification. The exposure apparatus according to claim 6, wherein when the second magnification is a low magnification, the step of the optical system is used to focus the optical system on the focus target surface. Exposing the substrate using the exposure apparatus according to claim 6 or 7,
Developing the exposed substrate. A device manufacturing method.

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