JP2008166612A - Laser device, aligner, control method, exposure method, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the image formation performance of a pattern image by controlling the characteristics of a laser beam. <P>SOLUTION: A main control device 50 controls the characteristics of a laser beam LB emitted from a laser device 16 (laser resonator 16a) by using wavelength width directly reflected to the image formation performance of a pattern image as an index value, performs scanning exposure by using the laser beam and generates a pattern image of a reticle R. Consequently the pattern image whose image formation state is controlled is generated. When a wafer W is exposed by the pattern image, a pattern is accurately formed on the wafer W. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser apparatus, an exposure apparatus, a control method, an exposure method, and a device manufacturing method. More specifically, the present invention relates to a laser apparatus capable of controlling the characteristics of laser light, an exposure apparatus using the laser apparatus as an exposure light source, and laser light. The present invention relates to a control method for controlling the characteristics, an exposure method using a laser beam with controlled characteristics, and a device manufacturing method using the exposure method.

  2. Description of the Related Art In recent years, sequential excitation exposure apparatuses such as steppers and scanning steppers (also called scanners) use a discharge excitation type spectrum narrowing pulse oscillation excimer laser as a light source. The pulse beam oscillated from this excimer laser passes through the illumination optical system of the exposure apparatus main body, and is irradiated to the photosensitive agent applied to the wafer surface placed on the wafer stage, the photosensitive agent is exposed, and the wafer is exposed. Is done.

  The spectral width of the laser beam is required to be narrowed due to the design of the optical system of the exposure apparatus, particularly the chromatic aberration tolerance. Conventionally, a specific upper limit is generally set for the spectral width for this narrow band quality, and the laser used for the light source of the exposure apparatus includes the above specific upper limit including fluctuations due to various factors. It was required to maintain the spectral width below the value. Band narrowing to a desired spectral width is achieved by optical elements such as a grating and an etalon (Fabry-Perot etalon).

  With the progressive movement type exposure apparatus, the numerical aperture (projection lens) of the projection optical system (projection lens) has been increased (with higher NA) as the pattern of the imaging target corresponding to the higher integration of semiconductor elements and the like has been further refined. As a result, the narrowing of the laser spectrum has progressed to the limit.

  Conventionally, full width at half maximum (FWHM) and spectral width E95% (also referred to as energy purity width E95) have been used as index values relating to the wavelength width for controlling the characteristics of laser light. (For example, refer to Patent Document 1).

  Here, FWHM is the wavelength width at the intersection between the intensity distribution curve of the spectrum of the laser light and the slice level corresponding to half the peak intensity. Further, the spectral width E95% means that the integrated value of the intensity distribution within the wavelength width between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level is 95 of the total integrated value (total energy) of the spectral intensity distribution. % Is the wavelength width.

  However, it is very troublesome to control the characteristics of the laser beam using the two index values in this way. Furthermore, neither FWHM nor% of the spectrum width E95 was directly reflected in the imaging performance of the pattern image.

  On the other hand, today, due to the refinement of device rules as the pattern of an imaging target (resolving target) becomes finer, the sensitivity of imaging with respect to the spectrum variation of laser light has become a level that cannot be ignored. .

  The inventor conducted various simulations (a part of which will be described later) under the above circumstances, and as a result, when many patterns such as a line-and-space pattern and an isolated line pattern are to be exposed. Regardless of illumination conditions, the integrated value of the intensity distribution within the wavelength width between the intersection points of the spectral intensity distribution curve of the laser beam and the predetermined slice level is the total integrated value (total energy) of the spectral intensity distribution. It has been found that the imaging performance of a pattern image can be controlled by controlling the characteristics of the laser beam using the wavelength width within a wavelength width range of a predetermined ratio as an index value.

  The present invention has been made on the basis of the above-described novel findings obtained by the inventor. From a first viewpoint, the present invention is a laser device that emits laser light, and a light source that generates the laser light; The wavelength at which the integral value of the intensity distribution within the wavelength width between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level is 89.6% to 94.3% of the total integrated value of the spectral intensity distribution. And a control device that controls the characteristics of the laser beam using a predetermined wavelength width within a width range as an index value.

  As will be described later, as a result of the simulation conducted by the inventor, the integrated value of the intensity distribution within the wavelength width between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level is the total integrated value of the spectral intensity distribution. It was confirmed that the wavelength width within the wavelength width range of 89.6% to 94.3% was directly reflected in the imaging performance of the pattern. Therefore, by using the laser apparatus of the present invention as a light source of a pattern forming apparatus that forms a pattern on an object such as an exposure apparatus, it is possible to adjust the image formation state of the pattern image.

  According to a second aspect of the present invention, there is provided an exposure apparatus for forming a pattern on an object, the laser apparatus of the present invention; and a pattern image formed on the object using laser light emitted from the laser apparatus. A pattern image generation device for generating a first exposure apparatus.

  According to this, since the pattern image generation device generates a pattern image on the object using the laser light emitted from the laser device of the present invention, the image formation performance of the pattern image on the object can be adjusted. As a result, a pattern can be accurately formed on the object.

  According to a third aspect of the present invention, there is provided an exposure apparatus that exposes an object with a pattern image, the laser light source emitting laser light; and the pattern image using the laser light emitted from the laser light source. A pattern image generating device to be generated; and a control device for controlling the characteristics of the laser beam using a wavelength width directly reflected on the imaging performance of the pattern image as an index value.

  According to this, the control device controls the characteristics of the laser light emitted from the laser light source using the wavelength width directly reflected in the imaging performance of the pattern image as an index value, and generates the pattern image using the laser light. A pattern image is generated by the apparatus. Thereby, a pattern image in which the imaging state is adjusted is generated. The pattern is accurately formed on the object by exposing the object with the pattern image.

  According to a fourth aspect of the present invention, there is provided an exposure apparatus that exposes an object with a pattern image, the laser light source emitting laser light; and the pattern image obtained by using the laser light emitted from the laser light source. A pattern image generating device to be generated; an integrated value of an intensity distribution within a wavelength width between intersections of a spectral intensity distribution curve of the laser beam and a predetermined slice level is set with respect to a total integrated value of the spectral intensity distribution And a control device that controls the characteristics of the laser beam using a wavelength width at a ratio corresponding to the pattern image generation condition as an index value.

  According to this, by the control device, the integrated value of the intensity distribution within the wavelength width between the intersection points of the spectral intensity distribution curve of the laser beam and the predetermined slice level is set with respect to the total integrated value of the spectral intensity distribution. The characteristic of the laser light emitted from the laser light source is controlled using the wavelength width at a ratio according to the image generation condition as an index value. Thereby, the characteristics of the laser beam are controlled according to the pattern image generation conditions. Then, the pattern image generation device generates a pattern image using the laser light whose characteristics are controlled, and the object is exposed with the pattern image. Therefore, it is possible to control the characteristics of the laser beam according to the pattern image generation conditions, and thus to form a highly accurate pattern on the object.

  According to a fifth aspect of the present invention, there is provided a control method for controlling characteristics of laser light emitted from a laser light source, the wavelength between the intersections of the spectral intensity distribution curve of the laser light and a predetermined slice level. The characteristic of the laser beam is determined by using, as an index value, a predetermined wavelength width within a wavelength width range in which the integrated value of the intensity distribution within the width is 89.6% to 94.3% of the total integrated value of the spectral intensity distribution. It is a control method including the process of controlling.

  As described above, according to the simulation performed by the inventor, the integrated value of the intensity distribution within the wavelength width between the intersection points of the spectral intensity distribution curve of the laser beam and the predetermined slice level is 89 of the total integrated value of the spectral intensity distribution. It was confirmed that the wavelength width within the wavelength width range from 0.6% to 94.3% is directly reflected in the imaging performance of the pattern. Therefore, by using the control method of the present invention to control laser light emitted from a laser light source that is a light source of a pattern forming apparatus that forms a pattern on an object such as an exposure apparatus, for example, an image formation state of the pattern image Can be adjusted.

  According to a sixth aspect of the present invention, there is provided an exposure method for forming a pattern on an object, the step of controlling the characteristics of laser light emitted from a laser light source by the control method of the present invention; And exposing the object using the laser beam to form a pattern on the object.

  According to this, the object is exposed using the laser light emitted from the laser light source whose characteristics are controlled by the control method of the present invention, and a pattern image is formed on the object. Therefore, it is possible to adjust the imaging performance of the pattern image on the object, and as a result, it is possible to form the pattern on the object with high accuracy.

  According to a seventh aspect of the present invention, there is provided an exposure method for exposing an object with a pattern image, wherein a laser beam emitted from a laser light source using a wavelength width directly reflected on the imaging performance of the pattern image as an index value And a step of generating a pattern image using the laser beam with the controlled characteristics.

  According to this, the characteristic of the laser beam emitted from the laser light source is controlled using the wavelength width directly reflected in the imaging performance of the pattern image as an index value, and the pattern image is generated using the laser beam. . Thereby, a pattern image in which the imaging state is adjusted is generated. The pattern is accurately formed on the object by exposing the object with the pattern image.

  According to an eighth aspect of the present invention, there is provided an exposure method for exposing an object with a pattern image, the wavelength width between the intersections of a spectral intensity distribution curve of laser light emitted from a laser light source and a predetermined slice level. Controlling the characteristics of the laser light using an index value as a wavelength width in which the integrated value of the intensity distribution is a ratio corresponding to the set pattern image generation condition with respect to the total integrated value of the spectral intensity distribution; And a step of generating a pattern image using the controlled laser beam.

  According to this, the integrated value of the intensity distribution within the wavelength width between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level is the set pattern image generation condition for the total integrated value of the spectral intensity distribution. The characteristic of the laser light emitted from the laser light source is controlled using the wavelength width corresponding to the ratio as an index value. Thereby, the characteristics of the laser beam are controlled according to the pattern image generation conditions. Then, a pattern image is generated using the laser light whose characteristics are controlled, and an object is exposed with the pattern image. Therefore, it is possible to control the characteristics of the laser beam according to the pattern image generation conditions, and thus to form a highly accurate pattern on the object.

  From a ninth viewpoint, the present invention is a device manufacturing method including a lithography step of exposing an object by any one of the first to third exposure methods of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 schematically shows a configuration of an exposure apparatus 10 according to an embodiment. The exposure apparatus 10 is a step-and-scan scanning exposure apparatus using a laser device as an exposure light source, that is, a so-called scanner.

  The exposure apparatus 10 holds an illumination system including a laser device 16 and an illumination optical system 12, and a reticle R illuminated by the illumination system, and holds a predetermined scanning direction (here, the Y axis in the horizontal direction in FIG. 1). A projection stage PU including a projection optical system PL that projects an image of the pattern of the reticle R onto the wafer W, a wafer that holds the wafer W and moves in the horizontal plane (XY plane) A stage WST, a liquid immersion device, and a control system for controlling them are provided.

As the laser device 16, an ArF excimer laser (oscillation wavelength 193 nm) is used as an example. As the laser device 16, in place of the ArF excimer laser, KrF excimer laser (oscillation wavelength 248.385 nm), F ₂ laser (oscillation wavelength 157 nm), as well as metal vapor laser, YAG laser, or semiconductor laser harmonic generation It is also possible to use a pulsed light source such as a device.

  As shown in FIG. 1, the laser device 16 includes a laser resonator 16a, a beam splitter 16b having a transmittance of, for example, about 97%, arranged on the optical path of the laser beam LB emitted from the laser resonator 16a, A beam monitor mechanism 16c disposed on the reflected light path of the beam splitter 16b, a laser control device 16e to which an output signal from the beam monitor mechanism 16c is input, and a laser power source whose power supply voltage is controlled by the laser control device 16e A portion 16d and the like are provided. As shown in FIG. 1, the constituent parts (16 a to 16 e and the like) of the laser device 16 are accommodated in a housing 17. The laser beam LB emitted from the laser resonator 16a and transmitted through the beam splitter 16b is incident on the illumination optical system 12 through a light transmitting portion of the housing 17 and a light transmission optical system (not shown).

  Note that either or both of the laser control device 16e and the laser power supply unit 16d can be disposed outside the housing 17.

  The laser resonator 16a includes an excimer laser tube (laser chamber) 64 including a discharge electrode, a total reflection mirror (rear mirror) 66 disposed on the back side (left side in FIG. 1) of the excimer laser tube 64, an excimer laser tube. 1 includes a low-reflectance mirror (front mirror) 68 disposed on the front side of 64 (the right side in the drawing in FIG. 1), a narrowband module 70 disposed between the excimer laser tube 64 and the front mirror 68, and the like. . In this case, a resonator is constituted by the rear mirror 66 and the front mirror 68 so that coherency is slightly increased.

  As an example, the narrowband module 70 is a fixed Fabry-Perot etalon (hereinafter referred to as “Fabry-Perot etalon”) that is sequentially disposed on the optical path of the laser beam LB between the excimer laser tube 64 and the front mirror 68. Abbreviation "etalon") and a variable tilt etalon. An etalon has two quartz plates facing each other in parallel with a predetermined gap (air gap) therebetween, and functions as a kind of band-pass filter. The fixed etalon is for coarse adjustment and the variable etalon is for fine adjustment. These etalons output the laser beam LB emitted from the laser resonator 16a with the spectral width narrowed to about 1/100 to 1/300 of the natural oscillation spectral width. Further, by adjusting the tilt angle of the etalon having a variable tilt angle, the wavelength (center wavelength) of the laser beam LB emitted from the laser resonator 16a can be shifted within a predetermined range.

  In addition, for example, the laser resonator may be configured by removing the coarse tuning etalon and providing a reflective diffraction grating (grating) as a wavelength selection element in a tiltable manner instead of the rear mirror 66. In this case, the grating and the front mirror 68 constitute a resonator. Further, a narrowband module having the same function as described above is constituted by the grating and the fine tuning etalon. In this case, the grating is used for coarse adjustment when setting the wavelength, and the etalon is used for fine adjustment. The laser device 16 is provided with a drive mechanism 19 for driving a spectroscopic element such as a variable tilt etalon (or a grating and a variable tilt etalon, or a grating or a prism). If the tilt angle of either the etalon or the grating is changed by the drive mechanism 19, the wavelength (oscillation wavelength) of the laser beam LB emitted from the laser resonator 16a can be changed within a predetermined range. Note that the band narrowing module may be configured by, for example, a combination of a prism and a diffraction grating (grating).

The excimer laser tube 64 is filled with a laser gas having a predetermined mixing ratio (this is composed of argon Ar as a medium gas, fluorine F ₂ and helium He as a buffer gas). For example, a flexible exhaust pipe is connected to the excimer laser tube 64 via an exhaust valve (not shown). This exhaust pipe is provided with a detoxifying filter that wraps fluorine, an exhaust pump, and the like. In consideration of the toxicity of fluorine, the exhaust gas is rendered harmless by an exclusion filter and then discharged to the outside of the apparatus by an exhaust pump.

In addition, one end of a flexible gas supply pipe is connected to the excimer laser tube 64 via a supply valve (not shown), and the other end of the gas supply pipe is a gas cylinder such as Ar, F ₂ , and He (not shown). It is connected to the. Each valve is controlled to open and close by the main controller 50. The main controller 50 adjusts the laser gas in the excimer laser tube 64 to have a predetermined mixing ratio and pressure, for example, at the time of gas exchange. In the excimer laser tube 64, laser gas is constantly circulated by a fan (not shown) during laser oscillation.

  Although not shown, the beam monitor mechanism 16c includes an energy monitor and a beam monitor (spectrum monitor). For example, the energy monitor is disposed on a reflected light path of a half mirror (not shown) disposed on the reflected light path of the beam splitter 16b. As this energy monitor, for example, a light receiving element such as a PIN photodiode having a high response frequency is used. A photoelectric conversion signal (light quantity signal) from the energy monitor is output to the laser control device 16e.

  As the beam monitor, for example, a Fabry-Perot interferometer including a condensing lens, a collimator lens, an etalon, a telemeter lens, a line sensor, and the like sequentially arranged on the reflection optical path of the beam splitter 16b is used. In this case, when the laser beam LB is incident on the etalon, the diffracted light (second wave based on Huygens principle) on the partially reflecting surface is repeatedly reflected and transmitted between the air gaps. At this time, only light in the direction of the incident angle θ satisfying the following formula (1) is transmitted through the etalon and strengthened, thereby forming an interference fringe (fringe pattern) on the focal plane of the telemeter lens. It is detected by a line sensor.

  2 · n · d · cos θ = mλ (1)

  Here, d is an air gap, n is the refractive index of the air gap, and m is an integer indicating the order. From formula (1), it can be seen that if n, d, and m are constant, the fringe pattern formed on the focal plane differs depending on the wavelength λ. The light intensity distribution detected by the line sensor is an intensity distribution waveform of the spectrum of the mountain-shaped laser beam LB corresponding to the interference fringes at a predetermined interval with respect to the longitudinal direction of the line sensor on the focal plane.

  FIG. 2 shows an example of the spectrum intensity distribution waveform. In FIG. 2, the horizontal axis represents wavelength and the vertical axis represents light intensity. Further, the integrated value of the intensity distribution within the wavelength width WD between the intersection points B and C of the laser beam LB and the predetermined slice level SL (that is, the area of the shaded area) is the total of the spectrum intensity distribution. The wavelength width WD when x% of the integral value (that is, the total area surrounded by the spectral intensity distribution curve and the horizontal axis: corresponding to the total energy value) is called the spectral width Ex%. In the present embodiment, a predetermined value, for example, the spectrum width E91.5%, of the wavelength width in the wavelength width range of the spectrum width E89.6% to the spectrum width E94.3% has the characteristics of the laser beam LB. It is used as a command value related to the wavelength width for control. This is because, as a result of the simulation conducted by the inventor, it was confirmed that the wavelength width within the spectral width range of E89.6% to E94.3% was directly reflected in the imaging performance of the pattern. is there. This point will be described later together with the simulation results.

  Further, the position in the longitudinal direction of the line sensor corresponding to the peak of the peak of each light intensity distribution is determined according to the center wavelength. That is, the above-described fringe pattern corresponds to the center wavelength and wavelength width (spectrum width) of incident light, and the image signal of this fringe pattern is transmitted from the beam monitor inside the beam monitor mechanism 16c to the laser control device. 16e.

  The laser power supply unit 16d includes a high-voltage power supply and a pulse compression circuit (switching circuit) that discharges a discharge electrode (not shown) inside the excimer laser tube 64 at a predetermined timing using the high-voltage power supply.

  The laser control device 16e includes an image processing circuit (including an AD converter and a peak hold circuit) that performs predetermined signal processing on the fringe pattern imaging signal and the output signal of the energy monitor, a microcomputer that performs predetermined calculation, and the like. including. The laser control device 16e performs predetermined signal processing on the image signal of the fringe pattern, so that information on the characteristics of the incident light (laser beam) LB with respect to the beam monitor mechanism 16c, for example, the center wavelength (or centroid wavelength) λ, the spectrum width Get information such as (wavelength width).

  Further, the laser control device 16e calculates the variation amount of the spectral width based on the difference between the spectral width and the reference value of the spectral width, for example, the initial spectral width. In addition, during normal exposure, the laser controller 16e controls the energy per pulse of the laser beam LB output from the laser resonator 16a based on the energy power detected based on the output of the energy monitor. The power supply voltage at the high voltage power supply inside the laser power supply unit 16d is feedback-controlled so that the value corresponds to the target value of energy per pulse given by the control information from the device 50. Further, the laser control device 16e controls the exposure timing for the shot area on the wafer W by controlling the application timing or application interval of the trigger signal to the pulse compression circuit in the laser power supply unit 16d based on the control information from the main control device 50. It also controls the number of pulses inside or the pulse oscillation repetition frequency (oscillation frequency).

  In addition, a shutter 16 f for shielding the laser beam LB in accordance with control information from the main controller 50 is also arranged on the illumination optical system side of the beam splitter 16 b in the housing 17 of the laser device 16.

  The illumination optical system 12 is a beam shaping optical system 18, a shaping optical system 20, an optical integrator (a fly-eye lens, an internal reflection type integrator, a diffractive optical element, or the like. In FIG. 1, a fly-eye lens is used. (Hereinafter also referred to as “fly-eye lens”) 22, illumination system aperture stop plate 24, beam splitter 26, first relay lens 28A, second relay lens 28B, fixed reticle blind 30A, movable reticle blind 30B, optical path bending mirror M and a condenser lens 32 are provided.

  The shaping optical system 20 is disposed behind the beam shaping optical system 18 that shapes the laser beam LB from the laser device 16. The molding optical system 20 includes, for example, a zoom optical system, a movable axicon (conical prism), as disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-345005 (corresponding US Patent Application Publication No. 2006/0170901). , And interchangeable diffractive optical elements.

  An illumination system aperture stop plate 24 is disposed on the optical path of the laser beam LB following the shaping optical system 20 via a fly-eye lens 22. The illumination system aperture stop plate 24 includes, for example, an aperture stop having a circular opening for normal illumination, an aperture stop for a small σ having a small circular opening and a small coherence factor (σ value), and an annular zone. A ring-shaped aperture stop for illumination, a modified aperture stop in which a plurality of apertures are arranged eccentrically for the modified light source method (only two of these aperture stops are shown in FIG. 1), etc. Has been placed. The illumination system aperture stop plate 24 is disposed in the vicinity of the exit surface of the fly-eye lens 22, that is, a surface that substantially coincides with the pupil plane of the illumination optical system in this embodiment.

  The illumination system aperture stop plate 24 is rotated by a driving device 40 such as a motor controlled by the main control device 50, and any one of the aperture stops is selectively set on the optical path of the illumination light IL, and the above-described molding optics is used. A zoom optical system inside the system 20, a movable axicon (conical prism), and a replaceable diffractive optical element are set. As a result, the shape and / or size of the surface light source composed of a number of point light sources formed on the pupil plane of the illumination optical system 12 by the fly-eye lens 22, that is, the secondary light source, can be freely changed. In the present embodiment, the intensity distribution of the illumination light IL on the pupil plane of the illumination optical system 12, that is, the illumination condition is changed by combining the shaping optical system 20 and the illumination system aperture stop plate 24. The illumination system aperture stop plate 24 is not necessarily provided. In addition, when an aperture stop having a variable aperture shape (including size) is used as various aperture stops included in the illumination system aperture stop plate 24, the shaping optical system 20 is not necessarily provided.

  A beam splitter 26 having a high transmittance is disposed on the optical path of the laser beam LB emitted from the illumination system aperture stop plate 24, that is, the illumination light IL, and the fixed reticle blind 30A and A relay optical system including the first relay lens 28A and the second relay lens 28B is disposed with the movable reticle blind 30B interposed therebetween.

  The fixed reticle blind 30A is disposed on a surface slightly defocused from the conjugate surface with respect to the pattern surface of the reticle R, and a rectangular opening that defines the illumination area IAR on the reticle R is formed. Further, a movable reticle blind 30B having a variable opening is arranged in the vicinity of the fixed reticle blind 30A, and further restricts the illumination area IAR via the movable reticle blind 30B at the start and end of scanning exposure, Unnecessary exposure is prevented.

  The illumination light IL emitted from the second relay lens 28B illuminates the reticle R via the optical path bending mirror M and the condenser lens 32. On the other hand, the illumination light IL reflected by the beam splitter 26 is received by an integrator sensor 46 including a photoelectric detector via a condenser lens 44, and the photoelectric conversion signal of the integrator sensor 46 is converted into a hold circuit (not shown) and an A / A. The output DS (digit / pulse) is supplied to the main controller 50 via a D converter or the like.

  On reticle stage RST, reticle R is held by suction using a vacuum chuck (not shown) or the like. The reticle stage RST can be finely driven in a horizontal plane (XY plane) by, for example, a linear motor type reticle stage drive system 48, and has a scanning direction (here, the Y-axis direction that is the left-right direction in FIG. 1). ) In a predetermined stroke range. The position of the reticle stage RST is measured by the reticle laser interferometer 54R using the mirror-finished side surface (reflection surface) of the reticle stage RST, and the measurement value of the reticle laser interferometer 54R is supplied to the main controller 50. .

  As shown in FIG. 1, the projection unit PU is disposed below the reticle stage RST. The projection unit PU includes a lens barrel 140 and a projection optical system PL having a plurality of optical elements held in the lens barrel 140 in a predetermined positional relationship. In the present embodiment, a catadioptric system is used as the projection optical system PL.

  In the exposure apparatus 10 of the present embodiment, since exposure using a liquid immersion method is performed, the aperture on the reticle side increases as the numerical aperture (NA) increases substantially. For this reason, in a refractive optical system composed only of lenses, it is difficult to satisfy Petzval's condition, and the projection optical system tends to be enlarged. In order to avoid such an increase in the size of the projection optical system, a catadioptric system is employed as the projection optical system PL.

  In the exposure apparatus 10, the projection optical system PL and a liquid Lq, which will be described later, constitute a substantial projection optical system, the numerical aperture (NA) of the projection optical system is 1.30, and the projection magnification is β times (β Is, for example, 1/4, 1/5, or 1/8). Therefore, when the reticle R is illuminated by the illumination light IL, a reduced image of the pattern of the reticle R in the illumination area IAR is projected onto the wafer W by the projection optical system (that is, an exposure area conjugate to the illumination area IAR). Projected to IA.

  In the present embodiment, at least one of the plurality of lenses of the projection optical system PL is driven by an imaging characteristic correction controller (not shown) based on a command from the main controller 50, and the projection optical system PL is The optical characteristics (including image formation characteristics) of the optical system including the magnification, distortion, coma aberration, field curvature (including image plane tilt), and the like can be adjusted.

  As shown in FIG. 1, the wafer stage WST is disposed above a base (not shown) below the projection optical system PL, and is moved in the XY plane (θz rotation) by a wafer stage drive system 56 including a linear motor and the like. Included). Wafer stage WST is rotated by an actuator that is a part of wafer stage drive system 56 in the Z-axis direction and in the direction of inclination with respect to the XY plane (rotation direction around X axis (θx direction) and rotation direction around Y axis (θy Direction)). Wafer stage drive system 56 may include an actuator that minutely moves wafer stage WST within the XY plane in addition to the Z-axis direction and the direction of inclination with respect to the XY plane. Wafer W is held on wafer stage WST by vacuum suction or the like via a wafer holder (not shown).

  Position and rotation of wafer stage WST in the XY plane (yawing (θz rotation that is rotation about the Z axis)), pitching (θx rotation that is rotation about the X axis), rolling (θy that is rotation about the Y axis) The rotation)) is always detected by the wafer laser interferometer 54 using a reflecting surface provided on the wafer stage WST.

  Position information (or speed information) of wafer stage WST is supplied to main controller 50. Main controller 50 controls wafer stage WST via wafer stage drive system 56 based on the position information (or speed information) of wafer stage WST.

  A reference mark plate FM on which a plurality of reference marks are formed is fixed at a predetermined position on wafer stage WST. The surface of the reference mark plate FM is flush with the surface of the wafer W held on the wafer stage WST.

  In the vicinity of the projection unit PU (for example, on the + Y side), an off-axis alignment system (not shown) for optically detecting a detection target mark such as an alignment mark on the wafer W is provided. As this alignment system, various types of sensors can be used. In this embodiment, for example, an image processing type sensor disclosed in, for example, Japanese Patent Laid-Open No. 4-65603 is used. An imaging signal from the alignment system is supplied to the main controller 50.

  Although not shown, above the reticle R, a pair of reticle alignment marks on the reticle R and a pair of reference marks formed on the above-described reference mark plate FM corresponding to the reticle R via the projection optical system PL. A pair of TTR (Through The Reticle) type reticle alignment systems that detect the positional relationship with the mark using light of the exposure wavelength are provided at a predetermined distance in the X-axis direction. As the reticle alignment system, one having the same configuration as that disclosed in, for example, Japanese Patent Laid-Open No. 7-176468 (corresponding US Pat. No. 5,646,413) is used.

  The liquid immersion apparatus includes a liquid supply unit 80, a liquid recovery unit 82, a nozzle member 90, and a piping system connected to these parts.

  The nozzle member 90 is around the lower end portion of the lens barrel 140 that holds an optical element on the most image plane side (wafer W side) constituting the projection optical system PL, here a lens (hereinafter also referred to as “front end lens”) 191. It is the annular member provided so that it might surround. The nozzle member 90 is connected to the supply port and the recovery port of the liquid Lq, the lower surface on which the wafer W is disposed and the recovery port is provided, and the supply flow connected to the liquid supply pipe 84 and the liquid recovery pipe 86, respectively. And a recovery channel.

  The liquid supply unit 80 is connected to the nozzle member 90 via a liquid supply pipe 84. The liquid supply unit 80 includes a tank that stores the liquid Lq, a temperature adjusting device that adjusts the temperature of the supplied liquid Lq, a filter device that removes foreign matter in the liquid Lq, a pressure pump, and a flow rate of the supplied liquid Lq. Including a flow control valve to be controlled. The liquid supply unit 80 is controlled by the main controller 50.

  The liquid recovery unit 82 is connected to the nozzle member 90 via a liquid recovery pipe 86. The liquid recovery unit 82 includes, for example, a vacuum system (suction device) such as a vacuum pump, a gas-liquid separator that separates the recovered liquid Lq and gas, a tank that stores the recovered liquid Lq, and a flow rate of the recovered liquid Including a flow control valve for controlling the flow rate. The liquid recovery unit 82 is controlled by the main controller 50.

  In the present embodiment, the liquid Lq is supplied between the tip lens 191 and the wafer W from the liquid supply unit 80 via the liquid supply pipe 84, the supply flow path, and the supply port at the time of exposure described later. The liquid Lq is recovered from between the front lens 191 and the wafer W by the liquid recovery unit 82 via the recovery port, the recovery flow path, and the liquid recovery tube 86, so that the front lens 191 and the wafer W are In the meantime, a certain amount of liquid Lq (see FIG. 1) is held. In this case, the liquid Lq held between the tip lens 191 and the wafer W is always replaced.

  The liquid supply unit 80 of the exposure apparatus 10 is not provided with all of the tank, the temperature adjustment device, the filter device, and the pressurization pump, but at least a part of them is replaced with equipment such as a factory where the exposure apparatus 10 is installed. You may do it. Further, the exposure apparatus 10 may not be provided with all of the vacuum system, the gas-liquid separator, the tank, and the flow rate control valve, but at least a part of them may be replaced with equipment of a factory where the exposure apparatus 10 is disposed.

  In this embodiment, the liquid Lq is filled with pure water having a refractive index of 1.44 with respect to illumination light (ArF excimer laser light) IL having a wavelength of 193 nm. Pure water transmits not only ArF excimer laser light but also ultraviolet light (g-line, i-line, etc.) emitted from a mercury lamp and far ultraviolet light (DUV light) such as KrF excimer laser light (wavelength 248 nm). Is possible.

  Note that the structure and arrangement of the liquid immersion device (the nozzle member 90, the liquid supply unit 80, the liquid recovery unit 82, etc.) are not limited to those described above, as long as a predetermined space in the optical path of the illumination light IL can be filled with the liquid. Various types of immersion apparatus can be applied.

  The control system includes a main controller 50 in FIG. 1, which is a so-called CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory) and the like. Including a microcomputer (or minicomputer), the entire apparatus is controlled in an integrated manner. The main control device 50 controls, for example, synchronous scanning of the reticle R and the wafer W, stepping of the wafer W, exposure timing, and the like so that the exposure operation is accurately performed.

Specifically, the main controller 50 synchronizes with the reticle R being scanned at a speed V _R = V in the + Y direction (or −Y direction) via the reticle stage RST at the time of scanning exposure, for example. Laser so that the wafer W is scanned through the stage WST in the −Y direction (or + Y direction) at the speed V _W = β · V (β is the projection magnification from the reticle R to the wafer W) with respect to the exposure area IA. Based on the measurement values of interferometers 54R and 54W, the positions and speeds of reticle stage RST and wafer stage WST are controlled via reticle stage drive system 49 and wafer stage drive system 56, respectively. At the time of stepping, main controller 50 controls the position of wafer stage WST via wafer stage drive system 56 based on the measurement value of laser interferometer 54W.

  Further, the main controller 50 controls the light emission timing, light emission power, and the like of the laser device 16 by supplying control information to the laser device 16 as described above. The main controller 50 also controls the illumination system aperture stop plate 24 via the shaping optical system 20 and the driving device 40, and further controls the opening / closing operation of the movable reticle blind 30B in synchronization with the operation information of the stage system. .

  As shown in FIG. 1, the main controller 50 is provided with a memory 51 and an input / output device 62 as storage devices. In the memory 51, the correlation coefficient (or correlation function) between the output DS of the integrator sensor 46 and the illuminance (intensity) of the illumination light IL on the surface of the wafer W, the output of the energy monitor, and the output of the integrator sensor 46 are stored. Information such as a correlation coefficient (or correlation function) with DS and the like, various information used for controlling the characteristics of the laser beam LB, for example, spectral characteristics, such as index values according to exposure conditions, and the like are stored. Yes.

  Here, a simulation performed by the inventor in order to obtain the above index value will be described.

  As the first exposure condition (pattern formation condition), ArF excimer laser light (wavelength 193 nm) is used as the illumination light for exposure, and the annular illumination condition where the coherence factor (σ value) is 0.25, the numerical aperture (NA) 1 .30 and an equal magnification catadioptric system as a projection optical system, an image of a first pattern (line and space pattern (L / S pattern) having a line width of 40 nm and a pitch of 110 nm) on a halftone mask having a transmittance of 6% Were set as exposure conditions for forming an L / S pattern image having a line width of 32 nm on the wafer.

  Further, as the second exposure condition (pattern formation condition), ArF excimer laser light (wavelength 193 nm) is used as the illumination light for exposure, and the numerical aperture (NA) is set under the annular illumination condition where the coherence factor (σ value) is 0.25. ) An image of the second pattern (L / S pattern having a line width of 40 nm and a pitch of 400 nm) on a halftone mask having a transmittance of 6% is used on the wafer by using a 1.30 catadioptric system as a projection optical system. Exposure conditions for forming an L / S pattern image having a line width of 32 nm were set.

  Further, as the third exposure condition (pattern formation condition), ArF excimer laser light (wavelength 193 nm) is used as the illumination light for exposure, and the shape of the secondary light source on the pupil plane is four circular regions decentered from the optical axis, Catadioptric refraction of NA 1.30 and equal magnification under quadrupole illumination conditions in which the circumscribed circle diameter of the four circular regions is 0.85 times the maximum diameter and the inscribed circle diameter is 0.55 times the maximum diameter. Using the system as a projection optical system, an image of a third pattern (contact hole pattern (C / H pattern) having a diameter of 70 nm and a pitch of 140 nm) on a halftone mask having a transmittance of 6% is formed on the wafer with a diameter of 70 nm. Exposure conditions were set.

  For the first to third exposure conditions, the spectral width Ex%, which is the index value of the wavelength width of the ArF excimer laser beam, is changed stepwise within a range of E95% to E89%, In response, a simulation was performed to acquire data on how the line width of the pattern image on the wafer changes.

  3 to 10 show the result of the above simulation. In these figures, the horizontal axis represents the spectral width Ex%, the left vertical axis represents the diameter of the image of the third pattern, and the right vertical axis represents the line width of the images of the first and second patterns.

  As is apparent from FIGS. 3 to 10, when the spectral width E91.5% in FIG. 7 is used as the index value, the change between the index value and the change in the line width or diameter of the pattern image is the most. It can be seen that there is a direct correspondence.

In this case, since it was confirmed that the change in the line width almost fits the quadratic curve in all of the first pattern, the second pattern, and the third pattern, the line width (diameter) change ∝ (E91.5%) ² relationship is established. For example, changes in the line widths of the first pattern and the second pattern were fitted to the quadratic curves represented by the following expressions (2) and (3), respectively.

y = −2.0221x ² −0.0042x + 32 (2)
y = 1.3767x ² −0.0056x + 32 (3)
FIG. 11 shows the line width variation expected when the spectrum width Ex% (energy purity width) changes. In FIG. 11, the horizontal axis represents the spectrum width Ex%, and the vertical axis represents the line width variation δCD.

  From FIG. 11, when the line width variation is allowed to 0.2 nm, the spectrum width E89.6% to E94.3% becomes a spectrum width that can be adopted as an index value, and the line width variation is allowed to 0.1 nm. Then, it can be seen that the spectrum width from about E90.7% to E92.8% is a spectrum width that can be adopted as the index value.

  Therefore, in the present embodiment, a value within the range of the spectral width E90.7% to E92.8%, for example, the spectral width E91.5%, is used for the exposure under the first to third exposure conditions described above. It is stored in the memory 51 as an index value used when controlling the characteristics of the beam LB.

  Although not shown, the inventor performed a simulation similar to the above for other exposure conditions (pattern formation conditions). As a result, in the third exposure condition described above, the spectral width E89% may be used as an index value in the fourth exposure condition using a C / H pattern having a diameter of 70 nm and a pitch of 140 nm instead of the third pattern. It was found that there is the most direct correspondence between the change in the index value and the change in the diameter of the pattern image.

  In this embodiment, it is assumed that the first to fourth exposure conditions (however, the actual use is assumed when the projection magnification of the projection optical system is β times) are assumed to be used. For each of these exposure conditions, the optimum spectral width Ex% is stored in the memory 51 in association with each exposure condition.

  In the exposure apparatus 10 of this embodiment, when manufacturing a device, the main controller 50 sets the illumination condition and sets the target based on the exposure condition specified in the exposure condition setting file, as in a normal scanning stepper (scanner). The reticle R on which the pattern is formed is loaded onto the reticle stage RST, the wafer is loaded onto the wafer stage WST, etc., followed by the reticle alignment system (not shown), the reference mark plate FM, and not shown. Using an alignment system such as a reticle alignment (this is performed with the liquid Lq held between the tip lens 191 and the reference mark plate FM), baseline measurement of the alignment system, and wafer alignment (for example, special Enhanced global alignment disclosed in Japanese Utility Model Publication No. 61-44429 Doo (EGA), etc.) is carried out. After completion of such preparatory work, a scanning exposure operation in which the reticle stage RST and the wafer stage WST are moved synchronously while the liquid Lq is held between the front lens 191 and the wafer W, and the wafer stage WST is moved into the shot area. After the exposure is completed, a step-and-scan exposure operation that alternately and repeatedly performs an inter-shot movement (stepping) operation that moves to an acceleration start position for exposure of the next shot area is performed, and a plurality of exposures on the wafer W are performed. A pattern image of the reticle R is formed in each shot area.

  At the time of the above scanning exposure, the main controller 50 reads the spectrum width Ex% corresponding to the exposure condition set at that time from the memory 51 and gives it to the laser controller 16e. Then, the characteristics of the laser beam LB are controlled by the laser controller 16e using the given spectrum width Ex% as an index value.

  For example, when any one of the first to third conditions is set as the exposure condition, the main controller 50 reads the spectrum width E91.5% from the memory 51 and gives it to the laser controller 16e. It is done. On the other hand, when the fourth condition is set as the exposure condition, the main controller 50 reads the spectrum width E89% from the memory 51 and gives it to the laser controller 16e. In any case, the laser controller 16e controls the characteristics of the laser beam LB during scanning exposure using the given spectrum width as an index value. Thereby, immersion exposure and scanning exposure are performed using illumination light (exposure light) IL whose spectral width is optimally adjusted in accordance with the set exposure conditions, and a desired line width of the wafer W is obtained. A pattern is formed.

  As described above, according to the exposure apparatus 10 according to the present embodiment, the imaging performance of the dense pattern such as the L / S pattern as a result of the simulation performed by the inventor at least under the first to third exposure conditions described above. The characteristic of the laser beam LB emitted from the laser device 16 (laser resonator 16a) at the time of scanning exposure is controlled by the laser control device 16e using the spectral width E91.5% that has been confirmed to be the most suitable as an index value. Then, an image of the pattern on the reticle R is formed (generated) on the wafer W using the laser beam LB, that is, the illumination light IL. In this case, it is possible to adjust the image formation state of the pattern. That is, a pattern image in which the imaging state is adjusted is generated. Then, by exposing the wafer W with this pattern image, a pattern is accurately formed on the wafer W.

  Further, according to the present embodiment, the integrated value of the intensity distribution within the wavelength width (WD) between the intersection points of the spectral intensity distribution curve of the laser beam LB and the predetermined slice level is calculated by the laser control device 16e. The laser beam LB (illumination) emitted from the laser resonator 16a (laser device 16) with the wavelength width and Ex% as a ratio corresponding to the set exposure condition (pattern image generation condition) with respect to the total integral value is used as an index value. The characteristics of the light IL) are controlled. In other words, the characteristics of the laser beam LB (illumination light IL) are controlled according to the exposure conditions according to the set exposure conditions (pattern image generation conditions). Then, reticle control RST and wafer stage WST are moved synchronously in the scanning direction by main controller 50 and scanning exposure is performed using laser beam LB (illumination light IL), so that reticle R held on reticle stage RST is performed. The pattern image is generated via the projection optical system (projection optical system PL and liquid Lq), and the shot area on the wafer W is exposed with the pattern image. Therefore, it is possible to control the characteristics of the laser beam according to the exposure conditions (pattern image generation conditions), and thus to form a highly accurate pattern on the wafer W.

  Further, in the exposure apparatus 10, since the above-described scanning exposure is performed by immersion exposure in which an image of the pattern of the reticle R is formed on the wafer W via the projection optical system PL and the liquid Lq, exposure with high resolving power is performed. It becomes possible.

  In the above embodiment, the spectral width E95% is used in the first to third exposure conditions described above as the index value for controlling the characteristics of the laser beam LB, and the spectral width E89 is used in the fourth exposure condition. % Is used, but the present invention is not limited to this. As can be seen from the graph of FIG. 11 described above, when the pattern to be exposed is a dense pattern, at least as in the first exposure condition to the third exposure condition, the spectral width E89.6% to E94. A wavelength width within a wavelength width range of 3%, more preferably a wavelength width within a spectral width range of E90.7% to E92.8%, is used as an index value when controlling the characteristics of a laser beam. Can do.

  In the above embodiment, in addition to the first to fourth exposure conditions, each of a larger number of exposure conditions (illumination conditions, NA of the projection optical system, and combinations of exposure target patterns) is the same simulation as described above. May be performed by setting the setting width of Ex% more finely to obtain the spectral width Ex% most corresponding to the imaging performance of the pattern image and storing it in the memory 51 for each exposure condition. Then, when manufacturing the device, the main controller 50 reads out the spectral width Ex% corresponding to the set exposure condition or the exposure condition closest to the set exposure condition from the memory 51 and gives it to the laser controller 16e. May be. When the spectrum width Ex% corresponding to the set exposure condition is not stored in the memory 51, the Ex% corresponding to the exposure condition closest to the exposure condition is changed to a laser beam (laser beam) as described above. However, the present invention is not limited to this. For example, the main controller 50 uses Ex% corresponding to a plurality of exposure conditions close to the set exposure conditions, respectively. A spectral width Ex% corresponding to the set exposure condition may be obtained by interpolation calculation or other calculations and used as an index value for controlling the characteristics of the laser beam.

  In the above embodiment, the main controller 50 reads the spectral width Ex% corresponding to the set exposure condition from the memory 51 and gives it to the laser controller 16e. However, the main controller 50 reads the spectral width Ex%. The characteristics of the laser beam may be controlled using Ex% as an index value. Further, instead of the above-described simulation, exposure is actually performed under the above-described first to fourth exposure conditions, and a pattern image (resist image) formed on the wafer W is converted into an SEM (scanning electron microscope) or the like. The relationship between the spectral width Ex% and the line width of the pattern image is obtained, and information on the optimum spectral width Ex% for each exposure condition obtained as a result is stored in the memory 51. good.

  So far, the case where the present invention is applied to an immersion exposure apparatus having a projection optical system with an NA exceeding 1.0 has been described, but the scope of the present invention is not limited to the immersion exposure apparatus.

  FIGS. 12 to 14 show examples of simulation results for the fifth exposure condition and the sixth exposure condition, which are exposure conditions (normal exposure conditions) that are not so-called immersion exposure.

  The fifth exposure condition (pattern formation condition) is ArF excimer laser light (wavelength 193 nm) as illumination light for exposure, and as an illumination condition, the shape of the secondary light source on the pupil plane is four circular regions decentered from the optical axis. Refraction of NA 0.92 and equal magnification under quadrupole illumination conditions where the circumscribed circle diameter of the four circular areas is 0.90 times the maximum diameter and the inscribed circle diameter is 0.75 times the maximum diameter. This is an exposure condition in which an image of a fifth pattern (C / H pattern having a diameter of 100 nm and a pitch of 270 nm) on a halftone mask having a transmittance of 6% is formed on a wafer with a diameter of 100 nm using the system as a projection optical system.

  The sixth exposure condition (pattern formation condition) is ArF excimer laser light (wavelength 193 nm) as exposure illumination light, and the illumination condition is four circular shapes in which the shape of the secondary light source on the pupil plane is decentered from the optical axis. Under the quadrupole illumination conditions where the diameter of the circumscribed circle of the four circular areas is 0.90 times the maximum diameter and the diameter of the inscribed circle is 0.75 times the maximum diameter, the NA is 0.92 and the same magnification Is used as a projection optical system under the exposure conditions for forming an image of a sixth pattern (C / H pattern with a diameter of 100 nm and a pitch of 900 nm) on a wafer with a diameter of 100 nm on a halftone mask having a transmittance of 6%. is there.

  As can be seen from FIGS. 12 to 14, it can be confirmed that, under the fifth exposure condition, the case where the spectral width E87% shown in FIG. 13 is changed has the highest correspondence with the line width change. Further, in the sixth exposure condition, it can be confirmed that when the spectrum width E90% shown in FIG. 14 is changed, the correspondence with the line width change is the highest. Therefore, when exposure is performed under the fifth exposure condition, the imaging performance of the fifth pattern can be adjusted by controlling the characteristics of the laser beam using the spectral width E87% as an index value. When exposure is performed under the sixth exposure condition, the imaging performance of the sixth pattern can be adjusted by controlling the characteristics of the laser beam using the spectral width E90% as an index value.

  In each of the above embodiments, as the illumination light IL, as disclosed in, for example, International Publication No. 1999/46835 pamphlet and corresponding US Pat. No. 7,023,610, a DFB semiconductor laser or fiber Infrared or visible single-wavelength laser light oscillated from the laser is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and ytterbium) and converted into ultraviolet light using a nonlinear optical crystal. Harmonic harmonics may be used.

As the light source, a light source that generates vacuum ultraviolet light such as Kr ₂ laser light having a wavelength of 146 nm or Ar ₂ laser light having a wavelength of 126 nm, or a mercury lamp that generates bright lines such as g-line or i-line is used. Also good.

  Further, the magnification of the projection optical system may be not only a reduction system but also an equal magnification or an enlargement system. The projection optical system is not limited to a catadioptric system, and may be either a reflective system or a refractive system, and the projected image may be an inverted image or an erect image.

  In the above embodiment, the case where the present invention is applied to a step-and-scan type scanning exposure apparatus and an immersion exposure apparatus has been described, but the present invention is not limited to this. The present invention can be applied not only to a static exposure type, for example, a step-and-repeat type or step-and-stitch type exposure apparatus, but also to a proximity type exposure apparatus, a mirror projection aligner, and the like. Further, as disclosed in, for example, International Publication No. 2001/035168, an exposure apparatus that forms an L / S pattern on a wafer by forming interference fringes on the wafer, for example, Japanese Translation of PCT International Publication No. 2004-51850. As disclosed in Japanese Patent Publication (corresponding US Pat. No. 6,611,316), two reticle patterns are synthesized on a wafer via a projection optical system, and one shot on the wafer is obtained by one scanning exposure. The present invention can also be applied to an exposure apparatus that performs double exposure of regions almost simultaneously.

  In the exposure apparatus of the above-described embodiment, a reticle pattern is transferred via a projection optical system as disclosed in, for example, Japanese Patent Laid-Open No. 10-214783 and International Publication No. 98/40791. A twin wafer stage type in which a wafer stage is arranged at each of the exposure position and the measurement position (alignment position) where mark detection by the wafer alignment system is performed, and the exposure operation and the measurement operation can be performed substantially in parallel. . Furthermore, as disclosed in, for example, JP-A-11-135400, JP-A-2000-164504, etc., a reference member that is movable independently of the wafer stage and on which a reference mark is formed and / or various photoelectric devices. The present invention can also be applied to an exposure apparatus including a measurement stage equipped with a sensor.

  In the above embodiment, a light transmissive 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 (also called a variable shaping mask) that forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed. For example, a DMD (Digital Micro-mirror Device) which is a kind of non-light-emitting image display element (spatial light modulator) may be used.

  Further, the use of the exposure apparatus is not limited to the exposure apparatus for semiconductor production, but for example, an exposure apparatus for manufacturing a display such as a liquid crystal display element formed on a square glass plate or the like, a thin film magnetic head Also, it can be widely applied to an exposure apparatus for manufacturing micromachines, DNA chips, and the like. 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 object to be exposed is not limited to a wafer, and may be, for example, a glass plate, a ceramic substrate, a film member, or mask blanks, and the shape is not limited to a circle but may be a rectangle.

  In the semiconductor device, a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and executing the above-described exposure method by the exposure apparatus of the above-described embodiment. The wafer is manufactured through a lithography step for transferring a reticle pattern onto a wafer, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like. In this case, in the lithography step, the exposure method described above is executed using the exposure apparatus of the above embodiment, and a device pattern is formed on the wafer. Therefore, a highly integrated device can be manufactured with high productivity.

  As described above, the laser apparatus of the present invention is suitable as a light source for a pattern forming apparatus such as an exposure apparatus. The control method of the present invention is suitable for controlling the characteristics of laser light emitted from a laser light source. The exposure apparatus, exposure method, and device manufacturing method of the present invention are suitable for manufacturing semiconductor devices and the like.

1 is a drawing schematically showing a configuration of an exposure apparatus 10 according to an embodiment. It is a figure which shows an example of a spectrum intensity distribution waveform. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E95% and the line width of a pattern image about the 1st-3rd exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between spectrum width E94% and the line width of a pattern image about the 1st-3rd exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E93% and the line width of a pattern image about the 1st-3rd exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between spectrum width E92% and the line | wire width of a pattern image about the 1st-3rd exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E91.5% and the line width of a pattern image about the 1st-3rd exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between spectrum width E91% and the line | wire width of a pattern image about the 1st-3rd exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E90% and the line width of a pattern image about the 1st-3rd exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E89% and the line width of a pattern image about the 1st-3rd exposure conditions. It is a graph which shows the relationship between energy width (spectral width Ex%) and the variation | expected line width variation. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E91.5% and the line | wire width of a pattern image about 5th, 6th exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E87% and the line width of a pattern image about 5th, 6th exposure conditions. It is a figure which shows an example of the simulation result which shows the relationship between the spectral width E90% and the line | wire width of a pattern image about the 5th, 6th exposure conditions.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus, 12 ... Illumination optical system, 16 ... Laser apparatus, 16a ... Laser resonator, 16e ... Laser control apparatus, 50 ... Main control apparatus, LB ... Laser beam, W ... Wafer, RST ... Reticle stage, WST ... Wafer stage, R ... reticle, PL ... projection optical system, Lq ... liquid, IL ... illumination light.

Claims (19)

A laser device that emits laser light,
A light source for generating the laser light;
The wavelength at which the integral value of the intensity distribution within the wavelength width between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level is 89.6% to 94.3% of the total integrated value of the spectral intensity distribution. And a control device that controls the characteristics of the laser beam using a predetermined wavelength width within the width range as an index value.   The control device uses the predetermined wavelength width within a wavelength width range in which the integrated value of the intensity distribution is 90.7% to 92.8% of the total integrated value as the index value, and the characteristics of the laser beam. The laser device according to claim 1, wherein the laser device is controlled. An exposure apparatus that forms a pattern on an object,
A laser device according to claim 1 or 2;
An exposure apparatus comprising: a pattern image generation device that generates a pattern image on the object using laser light emitted from the laser device. An exposure apparatus that exposes an object with a pattern image,
A laser light source for emitting laser light;
A pattern image generating device that generates the pattern image using laser light emitted from the laser light source;
An exposure apparatus comprising: a control device that controls the characteristics of the laser beam using a wavelength width that directly reflects the imaging performance of the pattern image as an index value.   In the control device, the integrated value of the intensity distribution within the wavelength width between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level is 89.6% to 94.94 of the total integrated value of the spectral intensity distribution. The exposure apparatus according to claim 4, wherein the characteristics of the laser beam are controlled by using a predetermined wavelength width within a wavelength width range of 3% as the index value.   The control device uses, as the index value, a predetermined wavelength width within a wavelength width range in which the integrated value of the intensity distribution is 90.7% to 92.8% of the total integrated value. 6. The exposure apparatus according to claim 5, which controls characteristics.   The exposure apparatus according to claim 6, wherein the control apparatus controls the characteristics of the laser light using a wavelength width at which an integrated value of the intensity distribution is 91.5% of the total integrated value as the index value. An exposure apparatus that exposes an object with a pattern image,
A laser light source for emitting laser light;
A pattern image generating device that generates the pattern image using laser light emitted from the laser light source;
The ratio of the integral value of the intensity distribution within the wavelength range between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level to the total integrated value of the spectral intensity distribution according to the set pattern image generation conditions An exposure apparatus comprising: a control device that controls the characteristics of the laser beam using the wavelength width as an index value. For a plurality of pattern image generation conditions, further comprising a storage device that stores a wavelength width of an optimal ratio with respect to the total integral value for each generation condition,
The control device selects a wavelength width optimum for a set pattern image generation condition from among a plurality of wavelength widths stored in the storage device, and uses the selected wavelength width as the index value for the laser. The exposure apparatus according to claim 8, which controls light characteristics. A control method for controlling the characteristics of laser light emitted from a laser light source,
The wavelength at which the integral value of the intensity distribution within the wavelength width between the intersections of the spectral intensity distribution curve of the laser beam and the predetermined slice level is 89.6% to 94.3% of the total integrated value of the spectral intensity distribution. A control method including a step of controlling the characteristics of the laser beam using a predetermined wavelength width within a width range as an index value.   In the controlling step, a predetermined wavelength width within a wavelength width range in which an integrated value of the intensity distribution is 90.7% to 92.8% of the total integrated value is used as the index value. The control method according to claim 10, wherein the characteristic is controlled. An exposure method for forming a pattern on an object,
A step of controlling characteristics of laser light emitted from the laser light source by the control method according to claim 10;
Exposing the object using the laser beam having controlled characteristics, and forming a pattern on the object. An exposure method for exposing an object with a pattern image,
Controlling the characteristics of the laser light emitted from the laser light source using the wavelength width directly reflected in the imaging performance of the pattern image as an index value;
And a step of generating a pattern image using the laser beam whose characteristics are controlled.   In the controlling step, as the index value, an integral value of the intensity distribution within the wavelength width between the intersection points of the spectrum intensity distribution curve of the laser beam and a predetermined slice level is 89 of the total integral value of the spectrum intensity distribution. The exposure method according to claim 13, wherein a predetermined wavelength width within a wavelength width range of 0.6% to 94.3% is used.   In the step of controlling, a predetermined wavelength width within a wavelength width range in which an integrated value of the intensity distribution is 90.7% to 92.8% of the total integrated value is used as the index value. 14. The exposure method according to 14.   16. The exposure method according to claim 15, wherein in the controlling step, a wavelength width at which an integrated value of the intensity distribution is 91.5% of the total integrated value is used as the index value. An exposure method for exposing an object with a pattern image,
Generation of a set pattern image in which the integral value of the intensity distribution within the wavelength range between the intersection points of the spectral intensity distribution curve of the laser light emitted from the laser light source and the predetermined slice level is the total integral value of the spectral intensity distribution A step of controlling the characteristics of the laser beam using a wavelength width that is a ratio according to conditions as an index value;
And a step of generating a pattern image using the laser beam whose characteristics are controlled.   The exposure method according to claim 17, wherein in the controlling step, a wavelength width that is selected from a plurality of wavelength widths and is optimal for a set pattern image generation condition is used as the index value.   A device manufacturing method including a lithography step of exposing an object by the exposure method according to claim 12.

Images