JP2007005525A - Photolithography apparatus and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent contamination of a beam-emitting end surface of an optical system due to watermarks or the like. <P>SOLUTION: Presence of a liquid between a tip lens (42) and a wafer (W) of a projection optical system (PL) is monitored constantly via a liquid detection sensor, provided on one of a feed pipe (21) and a recovery pipe (27) of a liquid soaking device (50). When water (Lq) is not filled between the lens (42) and the wafer (W), a laser beam LB is prevented from emitting, from a pulse light source (14) to an illumination unit IU. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exposure apparatus and a device manufacturing method. More specifically, the present invention relates to an exposure apparatus used in a lithography process for manufacturing an electronic device such as a semiconductor element (such as an integrated circuit) or a liquid crystal display element, and device manufacturing using the exposure apparatus. Regarding the method.

  Conventionally, in a lithography process for manufacturing an electronic device such as a semiconductor element (such as an integrated circuit) or a liquid crystal display element, a resist (sensitive material) is applied to a pattern image of a mask (or reticle) via a projection optical system. A step-and-repeat reduction projection exposure apparatus (so-called stepper) that projects onto each of a plurality of shot areas on a photosensitive object (hereinafter referred to as a wafer) such as a wafer or a glass plate; A scanning projection exposure apparatus (so-called scanning stepper) is mainly used.

  In this type of exposure apparatus, with the miniaturization of patterns due to the high integration of integrated circuits, higher resolution (resolution) has been required year by year. Recently, an exposure apparatus using an immersion method has attracted attention. It has come to be. As an exposure apparatus using this immersion method, an exposure apparatus that performs exposure in a state where the space between the lower surface of the projection optical system and the wafer surface is locally filled with a liquid such as water or an organic solvent is known (for example, a patent). Reference 1). The exposure apparatus described in Patent Document 1 utilizes the fact that the wavelength of exposure light in a liquid is 1 / n times that in air (where n is the refractive index of the liquid, usually about 1.2 to 1.6). As a result, the resolution can be improved and the depth of focus can be substantially increased n times compared to the air.

  However, in the immersion exposure apparatus, when all of the liquid between the lower surface of the projection optical system and the wafer surface is recovered (in the dry state), the liquid contact surface (the immersion area is formed) of the projection optical system. There is a possibility that the liquid remaining on the surface (the surface in contact with the liquid) is dried and an adhesion mark (a so-called water mark when the liquid is water) is formed.

  This adhesion mark becomes fogging of the projection optical system, causing a decrease in the transmittance of the projection optical system and a partial decrease in the transmittance with respect to the energy beam for exposure, resulting in a decrease in energy intensity on the wafer surface. And may cause unevenness of strength.

International Publication No. 2004/053955 Pamphlet

  Here, for convenience, the description will be made in association with the reference numerals of the drawings representing one embodiment, but the present invention is of course not limited to the embodiment.

  From the first viewpoint, the present invention is an exposure apparatus that exposes an object by irradiating the object (W) with an energy beam (IL) through an optical member (42) and a liquid (Lq). A liquid source that emits the energy beam; and an immersion space that forms an immersion space on the beam exit end side of the optical member in order to fill the beam path between the beam exit end side of the optical member with the liquid. A mechanism (21, 27, etc.); and a beam control system for preventing the energy beam from reaching the beam exit end of the optical member when the immersion space is not formed on the beam exit end side of the optical member. 20) and an exposure apparatus.

  According to this, when the beam path on the beam emission end side of the optical member is not filled with the liquid, it is possible to avoid the energy beam reaching the beam emission end surface of the optical member. Therefore, it is possible to suppress contamination of the beam emission end face of the optical member due to the adhesion mark of the liquid.

  From a second viewpoint, the present invention is a device manufacturing method including a lithography step of exposing an object using the exposure apparatus of the present invention and forming a device pattern on the object.

  According to this, since the device pattern is formed on the object by the exposure apparatus of the present invention, the decrease in energy intensity and the intensity unevenness on the object surface due to contamination of the beam exit end face of the optical member of the exposure apparatus are suppressed, As a result, productivity (including yield) of highly integrated devices can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic plan view of an exposure apparatus 10 according to the present invention.

  The exposure apparatus 10 is a step-and-scan scanning exposure apparatus that uses an excimer laser light source as a pulse light source as an exposure light source. The exposure apparatus 10 includes a pulse light source 14, an illumination unit IU, a reticle stage RST, a projection unit PU, a wafer stage device 60, and a control system thereof.

  The pulse light source 14 monitors a laser resonator, a beam splitter having a high transmittance and a slight reflectance, and a laser beam LB reflected by the beam splitter, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-095667. An energy monitor (beam monitor), an energy controller to which a photoelectric conversion signal from the energy monitor is supplied, a high voltage power source, and the like are provided.

  The laser beam LB emitted in a pulse form from the laser resonator enters the beam splitter, and the laser beam LB transmitted through the beam splitter at least partially includes an optical axis adjusting optical system called a beam matching unit (BMU). The light is emitted to the illumination unit IU through the light transmission optical system LB.

  During normal light emission, the energy controller uses a high-voltage power supply so that the energy controller has a value corresponding to the target value of energy per pulse supplied from the main controller 20 (not shown in FIG. 1, see FIG. 3). Feedback control of voltage. The energy controller also changes the oscillation frequency by controlling the energy supplied to the laser resonator via a high voltage power source.

  In addition, a shutter for shielding the laser beam LB in accordance with control information from the main controller 20 is also arranged outside the beam splitter in the pulse light source 14.

As the pulse light source 14, for example, an ArF excimer laser light source (output wavelength 193 nm) is used. In addition to the ArF excimer laser light source as the pulse light source 14, not only a KrF excimer laser light source (output wavelength 248 nm) and an F ₂ laser light source (oscillation wavelength 157 nm), but also a metal vapor laser light source, a harmonic generator of a YAG laser, etc. It is also possible to use a pulsed light source.

  The illumination unit IU includes an illumination system housing 70 and an illumination optical system inside the illumination system housing 70. As the illumination optical system, for example, Japanese Patent Laid-Open No. 2001-313250 (corresponding US Patent Application Publication No. 2003/0025890) and the like. As disclosed, the laser beam LB output from the pulse light source 14 includes an illuminance uniformizing optical system including an optical integrator, a beam splitter, a relay lens, a variable ND filter, a reticle blind, and the like (all not shown). With the shaped laser beam (hereinafter also referred to as illumination light) IL, the slit-shaped illumination area IAR elongated in the X-axis direction (the direction orthogonal to the paper in FIG. 1) on the reticle R is formed with substantially uniform illuminance. Illuminate.

  On reticle stage RST, reticle R on which a circuit pattern or the like is formed on its pattern surface (the lower surface in FIG. 1) is adsorbed by, for example, a vacuum adsorption system. The reticle stage RST can be driven minutely in the XY plane by a reticle stage drive system 11 (not shown in FIG. 1, see FIG. 3) including a linear motor, for example, and has a predetermined scanning direction (here, in FIG. 1). It can be driven at a scanning speed specified in the Y-axis direction, which is the left-right direction in the drawing.

  The position of the reticle stage RST in the stage moving surface (including rotation around the Z axis) is moved by a reticle laser interferometer (hereinafter referred to as a reticle interferometer) 16 to a movable mirror 15 (actually perpendicular to the Y axis direction). For example, a Y movable mirror having a reflecting surface and an X moving mirror having a reflecting surface orthogonal to the X-axis direction are provided). The measurement value of the reticle interferometer 16 is sent to a main control device 20 (not shown in FIG. 1, see FIG. 3). The main control device 20 uses a reticle stage drive system based on the measurement value of the reticle interferometer 16. 11 is used to control the position (and speed) of reticle stage RST in the X-axis direction, Y-axis direction, and θz direction (rotation direction about the Z-axis).

  Above the reticle R, a pair of reticle alignment systems 17 (however, the reticle alignment system on the back side in FIG. 1 is not shown) is arranged. As the pair of reticle alignment systems 17, for example, those similar to those disclosed in Japanese Patent Laid-Open No. 7-176468 are used.

  The projection unit PU is disposed below the reticle stage RST as shown in FIG. 1, and includes a lens barrel 40 and a plurality of optical elements held in a predetermined positional relationship within the lens barrel 40. And. As the projection optical system PL, for example, a refractive optical system including a plurality of lenses (lens elements) having a common optical axis AX in the Z-axis direction is used. This projection optical system PL is, for example, both-side telecentric and has a predetermined projection magnification (for example, 1/4 or 1/5). Therefore, when the illumination area IAR on the reticle R is illuminated by the illumination light IL from the illumination unit IU, the illumination light IL that has passed through the reticle R is illuminated via the projection optical system PL (projection unit PU). An area (hereinafter referred to as an exposure area) in which a reduced image of the circuit pattern of the reticle R in the area IAR (a reduced image of a part of the circuit pattern) is conjugated to the illumination area IAR on the wafer W coated with a resist (photosensitive agent). (Also called) IA.

  In the vicinity of an optical element (hereinafter referred to as the front lens) 42 closest to the image plane (closer to the wafer W) of the projection optical system PL, there is a liquid, for example, ArF, in the optical path space between the front lens 42 and the wafer W. At least a part of an immersion apparatus 50 that supplies pure water (hereinafter simply referred to as water) that allows excimer laser light (light having a wavelength of 193 nm) to pass therethrough is provided.

  As shown in FIG. 2, the liquid immersion device 50 is connected to the liquid supply device 52, the liquid recovery device 54, the supply pipes 21, 22, 23, 24 connected to the liquid supply device 52, and the liquid recovery device 54. Recovery tubes 27, 28, 29, 30 and the like. In FIG. 1, the supply pipe 21 and the recovery pipe 27 are representatively shown.

  The liquid supply device 52 includes a liquid tank, a pressure pump, a temperature adjustment device, and a plurality of valves (not shown) for controlling the start and stop of liquid supply to the supply pipes 21, 22, 23, and 24, respectively. I have. As each valve, for example, it is desirable to use a flow rate control valve so that not only the start and stop of liquid supply but also the flow rate can be adjusted. The temperature adjusting device adjusts the temperature of the liquid in the liquid tank to a temperature that is about the same as the temperature in a chamber (not shown) in which an exposure device centered on the projection unit PU, for example, is housed.

  One end of the supply pipe 21 is connected to the liquid supply device 52, the other end branches into three, and supply nozzles 21a, 21b, and 21c each formed of a tapered nozzle are formed at each branch end. The tips of these supply nozzles 21a, 21b, and 21c are positioned in the vicinity of the above-described tip lens 42 (see FIG. 1), are spaced apart in the X-axis direction, and are exposed by an exposure area IA (the illumination area on the above-described slit). And an area on the image plane conjugate to the + Y side. The supply nozzles 21b and 21c are arranged substantially symmetrically about the supply nozzle 21a.

  One end of the supply pipe 22 is connected to the liquid supply device 52, the other end branches into three, and supply nozzles 22a, 22b, and 22c each formed of a tapered nozzle are formed at each branch end. The tips of these supply nozzles 22a, 22b, and 22c are positioned in the vicinity of the tip lens 42, and are arranged at a predetermined interval in the X-axis direction and close to the −Y side of the exposure area IA. In this case, the supply nozzles 22a, 22b, and 22c are arranged to face the supply nozzles 21a, 21b, and 21c with the exposure area IA interposed therebetween.

  One end of the supply pipe 23 is connected to the liquid supply device 52, and a supply nozzle 23a composed of a tapered nozzle is formed at the other end. The tip of the supply nozzle 23a is located in the vicinity of the tip lens 42, and is arranged close to the −X side of the exposure area IA.

  One end of the supply pipe 24 is connected to the liquid supply device 52, and a supply nozzle 24a composed of a tapered nozzle is formed at the other end. The tip of the supply nozzle 24a is located in the vicinity of the tip lens 42, is disposed close to the + X side of the exposure area IA, and is opposed to the supply nozzle 23a across the exposure area IA.

  The liquid recovery device 54 includes a liquid tank and a suction pump, and a plurality of valves for controlling the start and stop of liquid recovery via the recovery pipes 27, 28, 29, and 30, respectively. As each valve, it is desirable to use a flow control valve corresponding to the valve on the liquid supply device 52 side described above.

  One end of the recovery pipe 27 is connected to the liquid recovery device 54, the other end is bifurcated, and recovery nozzles 27 a and 27 b each consisting of a divergent nozzle are formed at each branch end. In this case, the collection nozzles 27a and 27b are alternately arranged between the supply nozzles 22a, 22b, and 22c. The tips of the recovery nozzles 27a and 27b and the tips of the supply nozzles 22a, 22b, and 22c are arranged substantially along the same straight line parallel to the X axis.

  One end of the recovery pipe 28 is connected to the liquid recovery device 54, the other end branches into two branches, and recovery nozzles 28a and 28b each having a divergent nozzle are formed at each branch end. In this case, the collection nozzles 28a and 28b are alternately arranged between the supply nozzles 21a, 21b, and 21c and opposed to the collection nozzles 27a and 27b with the exposure area IA interposed therebetween. The tips of the collection nozzles 28a, 28b and the tips of the supply nozzles 21a, 21b, 21c are arranged substantially along the same straight line parallel to the X axis.

  One end of the recovery pipe 29 is connected to the liquid recovery device 54, the other end is bifurcated, and recovery nozzles 29a and 29b each consisting of a divergent nozzle are formed at each branch end. These recovery nozzles 29a and 29b are arranged with the supply nozzle 24a interposed therebetween. The tips of the collection nozzles 29a and 29b and the supply nozzle 24a are arranged substantially along the same straight line parallel to the Y axis.

  One end of the recovery pipe 30 is connected to the liquid recovery device 54, the other end is bifurcated, and recovery nozzles 30a and 30b each having a divergent nozzle are formed at each branch end. These collection nozzles 30a and 30b are arranged to face the collection nozzles 29a and 29b with the supply nozzle 23a and the exposure area IA, respectively. The tips of the collection nozzles 30a, 30b and the supply nozzle 23a are arranged substantially along the same straight line parallel to the Y axis.

  The liquid supply device 52 controls the valves connected to the supply pipes 21, 22, 23, and 24 according to instructions from the main control device 20, and supplies water Lq to the optical path space. At the same time, the liquid recovery device 54 controls the valves connected to the recovery tubes 27, 28, 29, and 30 according to an instruction from the main control device 20 to recover the water Lq from the optical path space. As a result, a certain amount of water Lq is circulated in the optical path space, and an immersion space is formed on the light exit end side of the tip lens 42.

  Liquid detection sensors 27c, 28c, 29c, and 30c are provided in the vicinity of one end of the recovery pipes 27, 28, 29, and 30 connected to the liquid recovery device 54 described above. These liquid detection sensors 27c, 28c, 29c, and 30c are, for example, capacitance-type sensors that detect water Lq by changes in the capacitance inside the collection tubes 27, 28, 29, and 30, or a refractive index. This is an optical sensor that detects the water Lq based on the change in the current, and outputs a current signal of, for example, 4 to 20 mA to the main controller 20 shown in FIG. 3 according to the detected liquid amount.

  Returning to FIG. 1, an off-axis alignment system (hereinafter referred to as an alignment system) ALG is provided on the side of the projection unit PU, for example, on the −Y side. The alignment system ALG is held by a holding member that holds the projection unit PU. As the alignment system ALG, various types of sensors can be used, but in this embodiment, an image processing type sensor is used. An image processing type sensor is disclosed in, for example, Japanese Patent Laid-Open No. 4-65603, and detailed description thereof is omitted here. The imaging signal from the alignment system ALG is supplied to the main controller 20 (see FIG. 3).

  Wafer stage device 60 includes base board 112, wafer stage WST disposed above the upper surface of base board 112, wafer table TB mounted on wafer stage WST, and wafer for measuring the position of wafer stage WST. Interferometer 18 and wafer stage drive system 12 (see FIG. 3) for driving wafer stage WST are provided.

  Wafer stage WST is provided with non-contact bearings (not shown), for example, air static pressure bearings (that is, air bearings (also referred to as air pads)) at a plurality of locations on the bottom surface. It is supported on the upper surface of the base board 112 through a clearance of about several μm by the static pressure of the pressurized air ejected toward the upper surface, and is driven in the XY plane by the wafer stage drive system 12 (including θz rotation). It has come to be.

  Wafer table WTB is mounted on wafer stage main body WST via a Z / leveling mechanism (not shown) (for example, equipped with an actuator such as a voice coil motor), and Z-axis direction and X-axis rotation with respect to wafer stage WST. Are rotated minutely by the Z-leveling mechanism in the rotation direction (θx direction) and the rotation direction around the Y axis (θy direction).

  On wafer table WTB, a wafer holder (not shown) for holding wafer W via a vacuum suction system or the like is provided. On the upper surface of wafer table WTB, a substantially rectangular plate (liquid repellent plate) 28 having a circular opening with an inner diameter slightly larger than the outer diameter of wafer W placed on the wafer holder is provided at the center. It has been. The plate 28 is set so that the surface thereof is substantially flush with the wafer W attracted and held by the wafer holder.

  The position of wafer stage WST is always detected by wafer interferometer 18 through the side surface (mirror-finished surface) of wafer table WTB with a resolution of about 0.5 to 1 nm, for example. Wafer interferometer 18 includes a Y interferometer for detecting the position of wafer stage WST in the Y-axis direction and an X interferometer for detecting the position of X-axis direction. The Y interferometer and the X interferometer are multi-axis interferometers having a plurality of measurement axes, and these interferometers rotate the wafer table WTB (θz rotation (rotation around the Z axis), θx rotation (rotation around the X axis). Rotation) and θy rotation (including rotation about the Y axis).

  The measurement value of wafer interferometer 18 is sent to main controller 20, and main controller 20 uses wafer stage drive system 12 and the X-axis direction of wafer stage WST based on the measurement value of wafer interferometer 18. The position in the Y-axis direction and the rotation are controlled.

  In addition, it is good also as providing the movable mirror which consists of a plane mirror instead of carrying out the mirror surface process of the wafer table TB.

  Furthermore, the exposure apparatus 10 of the present embodiment includes an irradiation system 90a and a light receiving system 90b (see FIG. 3) attached to a holding member (not shown) that holds the projection unit PU. An oblique incidence type multipoint focal position detection system similar to that disclosed in US Pat. No. 5,448,332) is provided.

  FIG. 3 shows the main configuration of the control system of the exposure apparatus 10. This control system is configured with a main controller 20 including a microcomputer (or workstation) that controls the entire apparatus as a whole. The main controller 20 is connected to a display device 95 such as a CRT monitor or a liquid crystal monitor.

  In the exposure apparatus 10 of the present embodiment configured as described above, an immersion space for the water Lq is formed by controlling the valves of the liquid supply apparatus 52 and the liquid recovery apparatus 54 of the immersion apparatus 50 by the main controller 20. In this state, reticle alignment using the reticle alignment system 17, baseline measurement of the alignment system ALG, and exposure preparation processing such as enhanced global alignment (EGA) are performed. In the above preparation process, part of the baseline measurement and wafer alignment are performed using the alignment system ALG, and thus are performed without using the water Lq.

  Then, an inter-shot moving operation for moving the wafer stage WST to the scanning start position (acceleration start position) for exposure of each shot area on the wafer W in the state where the immersion space of the water Lq is formed, and each shot An exposure process is performed by repeatedly performing a scanning exposure operation in which a pattern formed on the reticle R for the region is transferred by a scanning exposure method.

  The main controller 20 constantly monitors current signals from the liquid detection sensors 27c, 28c, 29c, 30c of the recovery tubes 27, 28, 29, 30 including at least the above-described exposure preparation process and exposure process, for example, When the value of the current signal of the liquid detection sensors 27c, 28c, 29c, and 30c is less than or equal to the threshold value, it is determined that a sufficient amount of water Lq is not filled in the optical path space, and the shutter inside the pulse light source 14 Is closed to shield the beam path of the laser beam LB.

  As described above, according to the exposure apparatus 10 of the present embodiment, the recovery pipes 27, 28, 29, and 30 connected to the liquid recovery apparatus 54 of the immersion apparatus 50 include the liquid detection sensors 27c, 28c, 29c, Since 30c is provided, the amount of water Lq recovered from the optical path space via the recovery pipes 27, 28, 29, and 30 can be constantly monitored. Thereby, for example, the water Lq is not sufficiently supplied to the optical path space, or the object such as the substrate is not below the front lens 42, so that the water Lq cannot be held below the front lens 42. If the water Lq in the recovery tubes 27, 28, 29, and 30 cannot be detected, it is determined that the desired immersion space is not formed, the shutter of the pulse light source 14 is closed, and the laser beam LB is emitted from the pulse light source 14. Prevents being injected outside. Therefore, when the immersion space is not formed, it is possible to prevent the illumination light IL from reaching the front lens 42 of the projection optical system PL, and as a result, contact of the front lens 42 such as formation of a watermark is achieved. The occurrence of contamination of the liquid level can be effectively suppressed.

  In the immersion exposure apparatus, the light exit end surface (wetted surface) of the tip lens 42 is in contact with water Lq containing the eluate from the wafer W (such as PAG contained in the resist applied to the wafer). If the illumination light IL is irradiated onto the liquid contact surface of the tip lens 42 in a state where the desired liquid immersion space is not formed on the light exit end side of the lens 42, the water Lq remaining on the liquid contact surface is left. May dry quickly and become a watermark, or the watermark already formed on the wetted surface may condense.

  In the present embodiment, illumination light (exposure light) IL is not irradiated onto the liquid contact surface of the tip lens 42 when a desired liquid immersion space is not formed on the light exit end side of the tip lens 42. Therefore, generation of watermarks and condensation of watermarks can be suppressed.

  In the above-described embodiment, the case where the liquid detection sensors 27c, 28c, 29c, and 30c are installed in the collection pipes 27, 28, 29, and 30 has been described. It may be installed at 22, 23, 24 to monitor the supply amount of water Lq. When a liquid detection sensor having a minute detection end is used, the detection end may be directly inserted between the tip lens 42 and the wafer W to detect the presence or absence of water Lq in the optical path space.

  Moreover, in the said embodiment, although the presence or absence of water Lq was detected by the liquid detection sensors 27c-30c based on the change of an electrostatic capacitance or a refractive index, instead of this, the flow volume of the water Lq which flows into a pipe line, for example is measured. Possible flow meters may be used. Or you may make it detect the presence or absence of water Lq using the above-mentioned multipoint focus position detection system. In short, it is sufficient that the presence or absence of water Lq can be detected regardless of the detection method.

  In the above embodiment, whether or not the immersion space of the water Lq is formed is detected, and the output of the illumination light IL is stopped based on the detection result. It is good also as controlling together. For example, main controller 20 prohibits output of laser beam LB to pulsed light source 14 when liquid supply device 52 is not in operation or when wafer stage WST does not exist below tip lens 42. The pulse light source 14 may be allowed to output the laser beam LB on condition that the liquid supply device 52 is in operation.

  Further, in the above embodiment, the case where the beam path of the laser beam LB from the laser resonator is shielded by closing the shutter has been described, but instead of this, or together with this, the output of the laser beam LB from the laser resonator. Is stopped, the illumination light IL may be prevented from reaching the front end lens 42 of the projection optical system PL. In short, the means is not particularly limited as long as the energy beam does not reach the beam exit end of the optical system when there is no immersion space. Therefore, a shutter may be provided in the projection optical system PL, the illumination unit IU, or the like, or the optical path of the illumination light IL may be blocked using a reticle blind or the like inside the illumination unit IU.

  In the above-described embodiment, the case where the immersion space for the water Lq is formed in a state where the tip lens 42 and the wafer W are opposed to each other is described. However, the tip lens 42 and another object (for example, the plate 28). ) Are opposed to each other, an immersion space for the water Lq can be formed between the tip lens 42 and another object. Therefore, illumination light (exposure light) IL is allowed to enter the front lens 42 even in a state where an immersion space of water Lq is formed between the front lens 42 and another object.

Moreover, in the said embodiment, although pure water (water) was used as a liquid, of course, this invention is not limited to this. As the liquid, a safe liquid that is chemically stable and has a high transmittance of the illumination light IL, such as a fluorine-based inert liquid, may be used. As this fluorinated inert liquid, for example, Fluorinert (trade name of 3M, USA) can be used. This fluorine-based inert liquid is also excellent in terms of cooling effect. In addition, a liquid that is transparent to the illumination light IL and has a refractive index as high as possible, and that is stable with respect to the projection optical system and the photoresist applied to the wafer surface (eg, cedar oil) is used. You can also When an F ₂ laser is used as the light source, a fluorine-based liquid (for example, fomblin oil) can be used as the liquid.

  In each of the embodiments described above, a refraction system composed of a plurality of lens elements (refractive elements) is employed as the projection optical system PL, but this is a catadioptric system that includes a reflective element and a refractive element. Alternatively, a reflection system that does not include a refractive element may be used.

  In each of the above embodiments, the optical element closest to the image plane of the projection optical system PL is the tip lens 42. However, the present invention is not limited to this, and the optical characteristics of the projection optical system PL, such as aberration (spherical aberration, It may be an optical plate (parallel flat plate or the like) used for adjustment of coma aberration or the like, or a simple cover glass.

  In each of the above-described embodiments, the optical path space on the emission side of the tip element (42) of the projection optical system PL is filled with liquid (water) to expose the wafer W. However, other optical paths in the projection optical system PL are used. The space may be filled with liquid (water). For example, as disclosed in the pamphlet of International Publication No. 2004/019128, the optical path space between the optical element facing the incident surface of the tip element and the tip element may be filled with liquid (pure water). . In this case, in a state where a desired immersion space is not formed between the optical element facing the incident surface of the tip element and the tip element, illumination light (on the emission surface of the optical element facing the incident surface of the tip element) The optical path of the illumination light (exposure light) IL may be blocked so that the exposure light) does not reach, or the emission of the laser beam LB from the light source 14 may be prohibited.

  A projection optical system including a plurality of lenses and a projection unit PU are incorporated in the exposure apparatus, and a liquid supply / discharge system is attached to the projection unit PU. Thereafter, optical adjustment is performed, a reticle stage and wafer stage made up of a number of mechanical parts are attached to the exposure apparatus, wiring and piping are connected, and further overall adjustment (electrical adjustment, operation check, etc.) is performed. The exposure apparatus of the embodiment can be manufactured. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  In each of the above embodiments, the case where the present invention is applied to a scanning exposure apparatus such as a step-and-scan method has been described. However, the scope of the present invention is of course not limited thereto. That is, the present invention can be suitably applied to a step-and-repeat reduction projection exposure apparatus. The present invention is also suitable for exposure of the same resist layer of the wafer W in a step-and-stitch type reduction projection exposure apparatus that synthesizes a shot area and a shot area.

  Further, as disclosed in, for example, Japanese Patent Laid-Open No. 6-124873, the present invention can be applied to an immersion exposure apparatus in which the entire surface of a wafer to be exposed is covered with a liquid. In the above-described embodiment, a light transmission type mask (reticle) in which a predetermined light shielding pattern (or phase pattern / dimming pattern) is formed on a light transmissive substrate is used. Instead of this reticle, for example, As disclosed in US Pat. No. 6,778,257, an electronic mask that forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed may be used.

  Further, as disclosed in International Publication No. 2001/035168, an exposure apparatus (lithography system) that forms a line and space pattern on a wafer W by forming interference fringes on the wafer W. The present invention can also be applied.

  Further, as described in, for example, European Patent Publication No. 1,041,357, the present invention also relates to an exposure apparatus provided with a measurement stage equipped with a measurement member and sensor in addition to the stage holding the substrate. Can be applied.

  For example, as disclosed in JP 2000-505958 (corresponding US Pat. No. 5,969,441), the present invention can also be applied to an exposure apparatus having a plurality of wafer stages.

  The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, but for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern to a square glass plate, an organic EL, a thin film magnetic head, an image sensor (CCD, etc.), micromachines, DNA chips and the like can also be widely applied to exposure apparatuses. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern.

The light source of the exposure apparatus of each of the above embodiments is not limited to an ArF excimer laser light source, but a pulsed laser light source such as a KrF excimer laser light source or an F ₂ laser light source, g-line (wavelength 436 nm), i-line (wavelength 365 nm). It is also possible to use an ultra-high pressure mercury lamp that emits such bright lines. Further, a single wavelength laser beam LB in an infrared region or a visible region oscillated from a DFB semiconductor laser or a fiber laser is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and ytterbium), and a nonlinear optical crystal You may use the harmonic which wavelength-converted into ultraviolet light using. The magnification of the projection optical system may be not only a reduction system but also an equal magnification or an enlargement system.

<Device manufacturing method>
Next, an embodiment of a device manufacturing method using the above-described exposure apparatus in a lithography process will be described.

  FIG. 4 shows a flowchart of a manufacturing example of a device (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). As shown in FIG. 4, first, in step 201 (design step), device function / performance design (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Subsequently, in step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

  Next, in step 204 (wafer processing step), using the mask and wafer prepared in steps 201 to 203, an actual circuit or the like is formed on the wafer by lithography or the like as will be described later. Next, in step 205 (device assembly step), device assembly is performed using the wafer processed in step 204. Step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.

  Finally, in step 206 (inspection step), inspections such as an operation confirmation test and durability test of the device created in step 205 are performed. After these steps, the device is completed and shipped.

  FIG. 5 shows a detailed flow example of step 204 in the semiconductor device. In FIG. 5, in step 211 (oxidation step), the surface of the wafer is oxidized. In step 212 (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step 214 (ion implantation step), ions are implanted into the wafer. Each of the above-described steps 211 to 214 constitutes a pre-processing process at each stage of wafer processing, and is selected and executed according to a necessary process at each stage.

  At each stage of the wafer process, when the above pre-process is completed, the post-process is executed as follows. In this post-processing process, first, in step 215 (resist formation step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the reticle (mask) is transferred to the wafer by the exposure apparatus and exposure method described above. Next, in step 217 (development step), the exposed wafer is developed, and in step 218 (etching step), the exposed member other than the portion where the resist remains is removed by etching. In step 219 (resist removal step), the resist that has become unnecessary after the etching is removed.

  By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the wafer.

  According to the device manufacturing method of this embodiment described above, the circuit pattern of the reticle is accurately transferred onto the wafer by the exposure apparatus and exposure method of the above embodiment in the exposure step (step 216). As a result, it becomes possible to improve the productivity (including yield) of highly integrated devices.

  As described above, the exposure apparatus of the present invention is suitable for exposing an object. The device manufacturing method of the present invention is suitable for manufacturing micro devices.

1 is a diagram showing a schematic configuration of an exposure apparatus 10 according to an embodiment of the present invention. 3 is a plan view showing a schematic configuration of a liquid immersion apparatus 50. FIG. 2 is a block diagram showing a configuration of a control system of exposure apparatus 10. FIG. It is a flowchart for demonstrating embodiment of a device manufacturing method. It is a flowchart which shows the specific example of step 204 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus, 14 ... Pulse light source, 20 ... Main controller, 50 ... Immersion apparatus, 52 ... Liquid supply apparatus, 54 ... Liquid recovery apparatus, 21-24 ... Supply pipe, 27-30 ... Recovery pipe, 42 ... Tip lens, 27c to 30c ... liquid detection sensor, W ... wafer, R ... reticle, IU ... illumination unit, PL ... projection optical system, IL ... illumination light, Lq ... water.

Claims (8)

An exposure apparatus that exposes an object by irradiating the object with an energy beam through an optical member and a liquid,
A beam source for emitting the energy beam;
An immersion mechanism for forming an immersion space on the beam exit end side of the optical member in order to fill the beam path on the beam exit end side of the optical member with a liquid;
And a beam control system for preventing the energy beam from reaching the beam exit end of the optical member when the immersion space is not formed on the beam exit end side of the optical member.   The exposure apparatus according to claim 1, wherein the beam control system prohibits emission of an energy beam from the beam source when the immersion space is not formed.   An opening / closing mechanism for opening / closing a beam path of the energy beam from the beam source to the exit end of the optical member; and the beam control system controls the opening / closing mechanism when the immersion space is not formed. The exposure apparatus according to claim 1, wherein the beam path is interrupted.   The exposure apparatus according to claim 1, further comprising a sensor that detects that the immersion space is not formed.   The liquid immersion mechanism includes a liquid supply mechanism that supplies liquid to form the liquid immersion space, and the sensor is disposed on a liquid supply path of the liquid supply mechanism. Item 5. The exposure apparatus according to Item 4. The immersion mechanism further includes a liquid recovery mechanism for recovering the liquid in the immersion space,
6. The exposure apparatus according to claim 4, wherein the sensor is disposed on a liquid recovery path of the liquid recovery mechanism.   The beam control system prevents the energy beam from reaching the beam emission end of the optical member when the immersion space is not formed in order to suppress contamination of the beam emission end surface of the optical member. An exposure apparatus according to any one of claims 1 to 6. A device manufacturing method including a lithography step of exposing an object using the exposure apparatus according to claim 1 to form a device pattern on the object.

Images